c & i Checklist

Sheet 1 of 3

Location Document Description Drawing No. / Ref. No.

Tab -1 Schemes Scheme of Air And Gas Path With Instrumentation 0-97-288-90090

Scheme of Tube Mill with Instrumentation 1-97-291-90125Location of MTM Thermocouples on SH/RH Tubes 0-97-293-90110Legend-1 2-97-096-90244Legend-2 2-97-096-90245Drum level control 2-97-096-90246Feed Control Valve DP Control 2-97-096-90247Furnace Draft Control 2-97-096-90248Primary Air PressureControl 2-97-096-90249Pulverised Coal Temperature Control 2-97-096-90250Co Ordinated Control 2-97-096-90251Air Flow Control 2-97-096-90252

Mill Load Preparation & 2-97-096-90253 2-97-096-90254Tube Mill Level Control 2-97-096-90255

SH-RH Steam Temperature Control & 2-97-096-90256 2-97-096-90257Drum level control 2-97-096-90258

Secondery Air Bypass Control 2-97-096-90259

Recommended Write-up On Auto Controls 4-97-096-90633

Recommended Write-up On Boiler House Auxiliaries Interlock And Protection System 4-97-096-90874

Measurement And Control Recommendation for Air And Flue Gas System 3-97-288-92118

Measurement And Control Recommendation for Air And Tube Mill System 3-97-288-92119

Measurement And Control Recommendation for Steam And Water & SB System 3-97-288-92120

Measurement And Control Recommendation for Fuel Oil System 3-97-288-92121

DIVISION - D

Controls And Instrumentation

VOLUME- D1Schemes , Shedules, FSSS, SADC and Soot Blower Controls

List Of Contents

0361 PARLI VOL D1 BHARAT HEAVY ELECTRICALS LIMITED

Sheet 2 of 3


Tab - 2 Schedules Schedule of Dampers 3-97-599-92163

Schedule of LT motors 3-97-599-92097Data for LT motors 3-97-599-92413Schedule of Servo motors 3-97-599-92244

Tab -3 Tapping point details Drum Dished End Instant Tapping Details 3-97-287-92174

Tapping drawings 4-97-288-90775Pressure measurement in A&FG furnace(Local & remote) 4-97-288-90776

Temperature measurement in furnace(Local & Remote) 4-97-288-90777

Analy. Meaurement in furnace(Local & remote) 4-97-288-90778

Pressure Measurement In Air & Flue Gas Duct 4-97-288-90779

Temperature Measurement In Air & Flue Gas Duct 4-97-288-90780Analyser Measurement in Air & FG duct(remote & test) 4-97-288-90782Temperature stub for Pressure parts 4-97-288-90783Test thermowell for PP 4-97-288-90784Stub For Sonic Tube Leak Detection System 4-97-288-90787Physical location of tapping points in furnace Region 1-97-599-90140

Tab-4 Furnace Safeguard Supervisor System Write-up on FSSS

FSSS Legend For Logic Drawing 3-95-094-13324Basic scope Diagram For FSSS 3-95-094-12973

List of Logic Diagrams to 3-95-094-13272 3-95-094-13324 FSSS Local Oil Gun Maintenance Switch Box 1-95-089-05320

List of Interconnection Diagrams to 3-95-094-13381 3-95-094-13416

DIVISION - D



List Of Contents


Sheet 3 of 3


Tab -5 Secondary air damper controls SADC write-up

Basic scope Diagram 3-95-194-12972

Shemes to 3-95-194-13130 3-95-194-13137

Tab -6 Soot Blower controls General write up on microprocessor based Soot blower

Wiring diagrams

Soot Blower System Basic Scope Drawing 2-96-185-01783

Interconnection Diagram For Soot Blower System to 3-96-186-08398 3-96-186-08415

Temperature Probe Control Scheme And Starter Box Arrangement 1-96-188-02700

SBMCC Schemes to 3-96-186-08018 3-96-186-08027

Tab -7 Operation and Maintenance Manual For Soot Blower Motor Control Centres(SBMCC)

Controls & Schematics Limited

DIVISION - D



List Of Contents


TAB - 1

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TRICHIRAPALLI

MAHARASHTRA STATE ELECTRICITY CORPORATION

NEW PARLI THERMAL POWER STATION EXTN. #1 1 X 250 MW BOILER,

810T/HR, 155 KG/CM (G), 540C / 540C Customer No: 0361

Drg. No.: 4-97-096-90633 Sheet 1 OF 10

RREECCOOMMMMEENNDDEEDD WWRRIITTEE UUPP OONN AAUUTTOO CCOONNTTRROOLLSS

Reference drawings: -

Sl.no Description Sheet no. Rev 01 Legend-1 2-97-096-90244 00 02 Legend-2 2-97-096-90245 00 03 Drum Level Control 2-97-096-90246 00 04 Feed Control valve DP Control 2-97-096-90247 00 05 Furnace Draft control 2-97-096-90248 00

06 Primary Air Pressure Control 2-97-096-90249 00

07 Pulverised Coal Temperature Control 2-97-096-90250 00 08 Coordinated Control 2-97-096-90251 00 09 Air Flow Control 2-97-096-90252 00

2-97-096-90253 00 10 Mill Load Preparation (Fuel Flow Control 1) Mill Load Preparation (Fuel Flow Control 2) 2-97-096-90254 00 11 Tube Mill Level Control 2-97-096-90255 00

12 SH / RH Steam Temp. Control 1 SH /RH Steam Temp. Control 2 2-97-096-90256 2-97-096-90257

00

13 LOFCV, HOTCV, ASPRV & SEAL AIR TO MILL DP Controls 2-97-096-90258 00

14 Secondary Air Bypass Control 2-97-096-90259 00

Name Date Drawing No Rev

Prepared S.Sankaranarayanan

Checked A.Chandramohan

Approved E.S.Salaikuberan 4-97-096-90633 00

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Drg. No.: 4-97-096-90633 Sheet 2 OF 10

DRUM LEVEL CONTROL: - Reference drg. No.: 2-97-096- 90246

The objective of this control system is to maintain the drum level to the normal water level at all loads. At lower loads (less than 30% MCR), start up feed control valve is used as final control element and at higher loads full load feed control valve is used as final control element. If the full load feed control valve is taken for maintenance, stand by feed control valve will be used. Drum level is measured at left and right side of the drum with level transmitters through temperature compensated constant head unit. Drum pressure is measured with pressure transmitters for compensation. The pressure compensated drum level signal is used for control. Excessive deviation between left and right side is alarmed and the control shall be tripped to manual. LOW LOAD:

At lower loads the full load control valve and stand by control valve shall be closed. The drum level measured signal is compared with the drum level set point. The error signal will have a proportional, integral and differential action in the single element controller. This controller output will be the position demand signal for the start up feed control valve. Auto/manual station is provided for auto/manual selection and operation. Position indicator is provided for the start up feed control valve.

HIGH LOAD:

At higher loads the start up and stand by full load control valve shall be closed. The pressure and temperature compensated steam flow shall be measured in the left and right main steam lines. These two flows are added for total steam flow. In order to prevent sudden response due to drum swell and shrink on load change, a time lag unit shall be included in the steam flow signal. The temperature compensated feed water flow signal is measured before feed control station. The error signal produced between drum level measured signal and drum level set point shall have proportional, integral and differential action in the three-element drum level controller. This will be added with steam flow signal, which is the feed water flow demand signal (set point for feed water flow). This will be compared with the feed water controller. Deviation if any will have a proportional and integral action in the feed water controller. This controller output will be the position demand signal for the full load feed control valve. Auto/manual station is provided for auto/manual selection and operation. Position indicator is provided for the full load feed control valves. FEED CONTROL VALVE DP CONTROL Reference drg.no. 2-97-096-90247.

The objective of this control system is to maintain the DP across the feed control valves to a constant set value. This is required to be maintained to supply feed water according to the requirement of the boiler at various loads. Differential pressure across the feed control station is measured with primary and redundant transmitters. These two signals are monitored and excessive deviation is alarmed and the control is tripped to manual. A transfer switch is provided to select the functioning transmitter and to defeat the comparison net work. The measured signal is compared with the DP set point and error is applied to a controller provided with proportional and integral action. The controller output is the positioning signal for the feed pump speed regulator. For boiler loads less than

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Drg. No.: 4-97-096-90633 Sheet 3 OF 10

30 % MCR, a minimum flow in the feed pump is ensured by the high signal selector. Separate auto/manual station is provided for each feed pump speed-regulating device. Speed indication of each feed pump shall be provided in the operator interface. However this control loop shall be decided based on the BFP requirement provided by BFP supplier. Refer the notes in the control scheme for interlocks.

FURNACE DRAFT CONTROL (ID FANS with Inlet DAMPER CONTROL and HYDRAULIC COUPLING) Reference drg.no. 2-97-096-90248: -

The main objective of the control is to maintain the furnace pressure constant at the desired set value at all loads. This is achieved by changing the flow of flue gas by modulating the inlet damper and varying the speed of the ID fan. Furnace pressure is measured by three transmitters and middle value auto selection is used to select the mid value. Recommended control range for the pressure transmitter is -250 mmwc to +250 mmwc excessive furnace pressure is monitored for directional block on ID fans. Furnace pressure is compared with set point and error will have proportional and integral action. FD fan demand signal is added as a feed forward feature. MFT feed forward feature is provided to minimize negative furnace pressure excursion. Separate AUTO / MANUAL station and position indicator for each ID fan-regulating device is provided. To have equal loading of the ID fans, each ID fan motor current is measured, averaged and compared. The difference is used for taking corrective action. The corrected signal is used to position the ID fans regulating units. The inlet damper position is monitored and compared separately with maximum and minimum position limit. The maximum and minimum position limit enables the inlet damper to be kept in its control range. The output will have proportional and integral action. The output from the controller is used to vary the speed of ID fan through VFD. Refer the notes in the control scheme for interlocks.

PRIMARY AIR HEADER PRESSURE CONTROL: Reference drg.no. 2-97-096-90249: - The objective of this control is to maintain the Hot Primary air header pressure at the desired value by adjusting the PA fan regulating unit. The Hot Primary air header pressure is measured using primary and redundant transmitters. Deviation between the above is alarmed and control is tripped to manual. The Hot Primary air pressure header pressure signal is compared with a set point in a PI controller. The controller output controls the PA fan-regulating unit. The set point of the PI controller is generated taking into consideration the following values:

a) The boiler load which increases the PA pressure on increasing boiler load. b) Minimum set value. c) Air to mill damper position (of mill AB, CD & EF-side DE and side NDE) which optimizes

the PA pressure to allow the Air to mill damper position with in a optimum range control (i.e between min. and max values as elaborated through function generator characteristic curve. To have equal loading of PA fan motor current is measured, averaged and compared. The difference is used to take corrective action. The corrected value is used to position the PA fan regulating units. Separate auto manual stations are provided with position indicator for PA fan regulating unit.

d) A transfer switch is provided to close/open and stay put the vane of each PA fan regulating unit whenever there is a command from the interlock system.

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Drg. No.: 4-97-096-90633 Sheet 4 OF 10

e) Refer the notes in the control scheme for the interlocks. PULVERISED COAL TEMPERATURE CONTROL Reference drg.no. 2-97-096-90250: -

The objective of this control is to maintain pulverized coal air temperature, at mill outlet at a constant value by action on the position of cold air regulating & hot air regulating dampers. The mill outlet temperature at both sides are measured and compared. The signal corresponding to the lower of the above two temperature is selected and compared with the set point in a proportional and integral controller. The output of the controller positions the cold air damper. A second loop controls the hot air regulating damper position in relation with the position of cold air regulating damper. This is in order to maintain the cold air damper in the optimum range of control typically between 40% to 80% damper opening. During half mill operation the side not in operation is rejected from the circuit by using a transfer switch. The transfer selects 100% signal from a signal generator. Since the lower of mill outlet temperature at two sides is selected, the signal from the not operation side signal generator is not selected. On mill starting the outlet temperature may not be adequate. Then the mill is set on a pre heat mode (contact from FSSS). A switching module switches the control from the above controller to a warm up controller. The mill inlet air temperature at common line is measured and compared with set point in a proportional and integral controller (warm up controller). The warm up controller output controls the cold air regulating damper position. Once the mill outlet temperature adequate condition is available set mill on preheat mode condition is removed through FSSS. A transfer switch is provided to close MILL-AB cold air regulating damper on MILL AB OFF condition from FSSS. Also a transfer switch is provided to close MILL-AB hot air regulating damper on MILL-AB OFF from FSSS. Separate auto manual station with position indication for cold air regulating dampers and hot air regulating dampers are provided. Refer the notes in the control scheme for interlocks.

CO - ORIDINATED MASTER CONTROL Reference drg.no. 2-97-096-90251: -

The main object of the co-ordinated control is to operate the turbine - generator and the steam generator as an integral unit. The desired generation of the boiler turbine combination will be established either by the operator unit load demand (ULD) setter or by a remote auto load despatch system (ADS). The desired generation signal (Target load) will be subjected to following limits. a) Operator set maximum generation limit (MW) b) Operator set minimum generation limit (MW) c) Maximum rate of change (mw per min.) When in load despatch mode, the maximum rate of change setter will permit the load despatch system to obtain slow rates. When in operator set mode, the new desired load will be achieved from the existing load at the rate set by the operator. The desired generation signal is further modified with generation error and frequency error, which will be adjusted to match the speed regulation inherent in the turbine governor. The frequency correction will be limited by the maximum/minimum generation settings, but will not be limited by the maximum rate of change of setter.

As the response of turbine is faster than the boiler, a second order delay is included in the turbine demand to match with boiler. The firing rate demand is modified by a throttle pressure

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Drg. No.: 4-97-096-90633 Sheet 5 OF 10

correction by means of PID control from throttle pressure set point and the actual value. MODES OF CONTROL: A) Co-ordinated control mode: -

The generation demand is applied to both boiler and turbine simultaneously in co-ordinated mode. When the system is in co-ordinated control mode, all run UPS and run downs, limit rate of change, frequency error, generation error and throttle pressure error will function automatically. If a run back action occurs while in the co-ordinated mode it will trip to base mode until operator desires

Base mode: -

In the base mode the demand for fuel and air will subject to maximum/minimum limit rate to change runback acting only will be applied. The generation and frequency error will not affect the demand signal.

Boiler flow mode: -

Whenever the capabilities of the turbine generator are exceeded or limited, the boiler load shall follow the turbine load.

Turbine follow mode: -

Whenever the capabilities of boiler and its auxiliaries are exceeded or limited, the turbine - generator shall follow the boiler. The run back will occur if any one of the two running FD/ID/PA fans, or boiler Feed pumps and number of elevations/feeders in service.

AIR FLOW CONTROL Reference drg.no. 2-97-096-90252: -

The secondary air flow is measured at left and right side of the ducts to wind box by means of aerofoils. Each flow will have temperature and pressure compensation. The flow is linearised by means of square root extractors. The total PA flow, obtained by summing the air flow through each mill in service, is added to obtain total air flow to the boiler. This signal is compared with the developed set point. The air flow demand from combustion control and actual fuel flow whichever is high (lead-lag system) is selected to ensure enrich combustion air. The oxygen in the flue gas at the inlet of AH is measured with primary & redundant transmitters. Transfer switch can be selected for either average value or individual value. This signal is compared with excess air set point and any error will have proportional and integral action to have better combustion efficiency. High/low limiters are used to limit the value in case the oxygen analyser is out of service. Under any circumstance the air flow should not be less than 30% MCR flow. This signal is the developed set point for the air flow control. Any difference between the developed set point and the air flow signal will have proportional and integral action in the air flow controller. This position demand signal will be selected to the corresponding FD fans in service through auto / manual stations. Equal loading of FD fans are achieved by measuring the motor current. Necessary interlock from FSSS, boiler auxiliaries interlock system, maximum deviation limit (MDL) etc. are provided. Position indicator for each FD fan regulating device is provided.

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Drg. No.: 4-97-096-90633 Sheet 6 OF 10

Refer the 'notes' with control scheme for interlocks. TUBE MILL LOAD REPARTITION (FUEL FLOW CONTROL - 1 & 2 ) Reference drg.no. 2-97-096-90253 & 2-97-096-90254.

The objective of the control is to vary the fuel flow so as to maintain the main steam pressure constant. The fuel demand signal (from combustion control) and total air flow (from air flow control) corrected for fuel air ratio are compared in a low signal selector. This is to ensure that fuel flow never exceeds the actual airflow. The lesser of fuel demand or total air flow is selected and compared with the fuel flow signal. The difference will have proportional and integral action in the fuel flow controller. Necessary auto manual station is provided for common and individual mill control. In tube mill, the fuel flow to the burners is directly proportional to the actual air flow to the mill. Hence the actual fuel flow is measured by adding air flow (temperature compensated) to each mill side (from tube mill controls) and heavy oil flow . Mill load demand (side NDE) is compared with actual coal flow (side NDE mill air flow). Any deviation shall have proportional and integral action to position the air to mill control damper and inturn varies the mill air flow. Total primary air flow is the sum of bypass air and air flow to the mill. Bypass air flow is required in order to have sufficient velocity in pulverised coal pipe at all loads. The sum of air through the mill and bypass air demand is a function of air flow through the mill. The set point for the bypass air flow demand is a function of the actual Mill air flow demand signal. This set point is compared with the actual bypass airflow. Any deviation shall have proportional and integral action to position bypass air dampers. Actual air flow to mill (side NDE) is also taken for secondary air damper control system. High & low signal monitors are used to generate mill air flow 60% contacts for use in FSSS. Actual air flow to mill (side NDE) is added with bypass air flow to mill (side NDE) to get PA flow for each mill (side NDE). Similarly, PA flow for each mill (side DE) is measured. Both the above are added to get PA flow for each mill. Three such signals (for MILL AB, CD & EF) are added to get total PA flow only when the condition Mill on load from FSSS is present the air to mill signal (side NDE) is allowed for further processing in mill load preparation. Whenever the condition filling value from FSSS is present, a transfer switch switches to a control signal equal to a 30% of mill air control damper (side NDE) position. Also, whenever the condition preheat mode from FSSS is present, a transfer switch switches to a control signal which varies in accordance to a ramp function, 0-30% air flow demand in 5 minutes. Auto manual stations are provided with position indication for mill air control damper and mill bypass air control damper. Refer the notes in the control scheme for interlocks. TUBE MILL LEVEL CONTROL Reference drg.no. 2-97-096-90255: -

The objective of this control is to maintain a constant coal level in the mill. Coal level is measured as a function of differential pressure across the mill. The feed rate signal of each gravimetric feeder in side DE & NDE of each mill is compared with the set point in proportional and integral controller. The output of this controller regulates the feeder speed. The differential pressure across the mill is measured on side DE & NDE of the mill. The greater of the two signals is selected and compared with the set point in a proportional and integral controller. The output of this controller forms the set point for the feeder speed controller.

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Drg. No.: 4-97-096-90633 Sheet 7 OF 10

When the differential pressure tapping are under purge sequence the mill DP signal is frozen to the earlier value in a memory. The contact for freezing is taken from FSSS. Separate auto manual station and feeder speed indication are provided for each feeder. A transfer switch is provided to select a control signal from a function generator wherever the conditions filling up value" is present from FSSS. The function generator gives a ramp output for feeder speed with respect to time. A transfer switch is provided to run feeder speed set point to minimum whenever there is a command from FSSS. High & low signal monitors are used to generate DP 27% contact for use in FSSS. Refer the notes in the control scheme for interlocks.

SH / RH - STEAM TEMPERATURE CONTROL Reference drg.no. 2-97-096-90256 & 2-97-096-90257: -

General

Steam temperature control is provided by a combination of burner nozzle tilt positioning and SH, RH de-superheating spray. Allowing nozzle tilt to respond to the lower of either SH or RH outlet temperature maintains steam temperature, with spray responding to the higher. Auto/manual stations are to be provided for modulating the following: 1 SH spray water valve - left 2 SH spray water valve - right 3 RH spray water valve - left 4 RH spray water valve - right 5 Burner tilts power cylinder. Each measurement is manually selectable between a primary and redundant element. Each pair of elements is compared and excessive deviation between the primary and redundant is alarmed, with control rejected to manual. SH SPRAY WATER VALVE CONTROL

In the automatic mode, each SH spray water valve is controlled by a cascade control. Under normal conditions average SH outlet temperature (Tsho), the primary controlled variable, is in the outer loop of the cascade control for each valve. SH DESH outlet temperature (Tshdso), an index of the immediate effect of spray valve operation, is in the inner loop. The outer loop PID controller receives an error signal equal to the average deviation of Tsho set point and each measured final SH (left and right) outlet temp. (Tshol and Tshor). The Tsho set point is programmed as a function of unit steam flow for constant pressure operation. The outer loop controller establishes a set point for the SH DESH outlet temp. This set point is compared to measured Tshdso and the resulting error is used to position the SH spray valves.

If the deviation between Tsho set point and measured Tshol or Tshor exceeds a preset high limit, control of the outer cascade loops is transferred from average Tsho to the individual final SH outlet temperature, Tshoa and Tshob. Strong feed forward to the SH temperature control which interact with each other are provided. These feed forwards are needed to compensate for over firing and under firing which may be required initially. When changing unit load, feed forward signals are utilised as follows (using unit load increase as an example): 1. The rate of change of fuel demand increase (an indication of over firing) is used to open the SH spray valves to counter the initial temperature rise. 2. Drum pressure and steam flow (applied inversely to spray valve demand) and tilt position

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Drg. No.: 4-97-096-90633 Sheet 8 OF 10

(applied directly) are used as an index to recognize the tendency for temperature to drop after item-1 above occurs, and is used to close the SH spray valves to counter the subsequent temperature drop. Interlocks are provided to close the SH spray valves at loads less than 20% MCR. RH SPRAY WATER VALVE CONTROL

In the automatic mode, each RH spray water valve is controlled by a cascade control. Under normal operating conditions RH outlet temperature (Trho), the primary controlled variable, is in the outer loop of each cascade control; RH DESH outlet temperature (Trhdso), an index of the immediate effect of spray valve operation, is in the inner loop. The outer loop PID controller receives an error signal final RH (left and right) outlet temperature (Trhol and Trhor). The Trho set point is programmed against the main steam flow curve, for constant pressure operation. The outer loop controller output is modified with tilt position to establish a set point for the RH DESH outlet temperature. This set point is compared to measured Trhdso, and the resulting error is used to position the associated RH DESH spray water valve. If the deviation between the Trho set point and the individual measured final RH outlet temperature exceeds a preset high limit, control of the outer cascade loops is transferred from average Trho to the individual measured final RH outlet temperature (Trhol and Trhor) to allow spraying of the hot lead. Interlocks are provided to keep the spray valves closed at loads less than 20% MCR. Nozzle tilt control

The average Tsho and Trho error signals are compared and the greater of the two errors (i.e., The lower of the two temperatures), is selected for nozzle tilt control. An interlock is provided to keep the tilts at their base (horizontal) position at loads less than 25% MCR. If any spray water valve opens fully, the tilt control is interlocked to disallow further raising of the tilts, and thus prevent possible over heating of the SH and RH outlet lead. OVERALL STEAM TEMPERATURE CONTROL: Typical operation :

1.At loads less than 20% MCR, SH and RH spray water valves are maintained closed. At loads

less than 25% MCR, the nozzle tilts are maintained at their horizontal position.When loading reaches 25% MCR, and with no SH or RH spray demand, the lower of either Trho (average) or Tsho (average) is selected for tilt control.

2. If, for example, trho (average) is less than Tsho (average), Then trho will assume control of the nozzle tilts. At that time, transfers will occur to add a bias to the outer loop of each RH cascade control, and remove the bias from each SH cascade control. This insures that the RH spray water valves remain closed while tilts are on RH control, except in emergency high temperature conditions. In these situations, if the average Trho error exceeds the bias, the RH spray water valves are allowed to open to lower the temperature in the associated lead.

3. While tilts are on RH control, if Tsho goes higher than set point, the SH spray water valves are allowed to modulate as necessary to maintain Tsho set point. When a SH spray water valve begins to open, a transfer occurs to add a negative bias to the Tsho error. This prevents the

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Drg. No.: 4-97-096-90633 Sheet 9 OF 10

immediate temperature lowering action of SH sprays from falsely shifting tilt control to average SH temperature which may be momentarily lower. When the associated SH spray water valve closes, the bias is automatically removed from the Tsho error signal. If Tsho (average) should become less than Trho (average), tilt control will be transferred to SH control and the overall operation will be the converse of the above example.

LIGHT FUEL OIL FLOW CONTROL Reference drg. No.: 2-97-096-90260

The purpose of the control system is to maintain the flow required LFO flow by maintaining constant pressure. The pressure after fuel oil flow control valve is measured with primary and redundant transmitters. Deviation is alarmed and the controller is tripped to manual. The selected signal is compared with the set point. The error will have proportional and integral action. The controller output will be the position demand signal for the flow control valve located in the fuel pump house. Auto/manual station is provided for auto/manual selection. Position indication is provided for the fuel oil pressure control valve. HEAVY FUEL OIL FLOW CONTROL Reference drg. No.: 2-97-096-90258

The purpose of the control system is to maintain the required HFO flow by maintaining constant pressure in the header. The pressure after flow control valve is measured with primary and redundant transmitters. Deviation is alarmed and the controller is tripped to manual. The selected signal is compared with the set point. The error will have proportional and integral action. The controller output will be the position demand signal for the flow control valve located in the fuel oil line. Auto/manual station is provided for auto/manual selection for operation. Position indication is provided for the heavy fuel oil flow control valve. ATOMISING STEAM PRESSURE CONTROL Reference drg. No.: 2-97-096-90258

The purpose of the control system is to maintain the pressure of atomising steam line at the required value. The atomising steam pressure is measured with primary and redundant transmitters. Deviation is alarmed and the controller is tripped to manual. The selected signal is compared with the set point. The error will have proportional and integral action. The controller output will be the position demand signal for the atomising pressure control valve. Auto/manual station is provided for auto/manual selection. Position indication is provided for the atomising pressure control valve.

SEAL AIR TO PRY. AIR INLET DP CONTROL Reference drg.no. 2-97-096-90258

The objective of this control system is to maintain the DP across seal air common header to primary air at mill inlet to a constant set value. This is required to avoid coal and coal dust entry to the rotating parts of tube mills and feeders at various loads. Differential pressure across seal air common header to primary air inlet to mill measured with diff. Pressure transmitter. The measured signal is compared with the DP set point and error is applied to a controller provided with proportional and integral action. The controller output is the positioning signal for the pneumatically operated damper's regulator. Separate auto/manual station is provided for this

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Drg. No.: 4-97-096-90633 Sheet 10 OF 10

damper. Position indication of each damper shall be provided in the operator interface.

SECONDARY AIR BYPASS CONTROL (manual)

The main objective of this control is to maintain the flue gas temperature above the dew point by manually operating the Secondary air duct damper during start up condition low load condition (HLA 10 AA201) from remote (DCS). This operation has to send the cold secondary air partially through the BYPASS DUCT. So that required average cold end temperature, above the dew point can be achieved depending upon the ambient temperature.

]]]]]

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MAHARASHTRA STATE ELECTRICITY BOARD NEW PARLI THERMAL POWER STATION 1 X 250 MW BOILER, UNIT # 1 810T/HR, 155 KG/CM (G), 540C / 540C Customer No: 0361

RECOMMENDED WRITE UP ONBOILER HOUSE AUXILIARIES

INTERLOCK & PROTECTION SYSTEM

BCR NO: 501

Sheet 11 of 15

PREPARED S.Sankaranarayanan --sd-- Date 30/9/04 Drawing No Rev

CHECKED A.Chandramohan --sd-- 30/9/04

APPROVED E.S.Salaikuberan --sd-- 30/9/04 4-97-096-90874 010

Revision Date Checked

01 21.12.04 Approved

Corrected as per MSEB marked up comments vide their letter No: 3503 dtd 1.12.04 and our reply.

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MAHARASHTRA STATE ELECTRICITY BOARD NEW PARLI THERMAL POWER STATION 1 X 250 MW BOILER, UNIT # 1


Drg. NO.: 4-97-096-90874 /01

PARLIint.doc Sheet 2 of 16

GENERAL:

To-days steam generators are larger in size and sophisticated in nature. Failure of any equipment calls for expensive replacement and results in costlier down time. This emphasizes careful planning on the correct procedure for 1. Safe sequence of start-up of equipments in the power plant. 2. Continuous trouble free & efficient operation. 3. Safe sequence of shut down of the equipment when needed.

This also leads to provision of adequate and reliable protection to safeguard the various plant equipments under abnormal and dangerous conditions. The operation of the protections shall be accompanied by visual and audible annunciation, which provide definite indication of the primary cause or causes of operation of the protection. Restarting of the equipment, which has once been tripped by protection either by remote, automatic or manual control shall be possible only after the elimination of the cause of tripping.

PROTECTIONS ARE CLASSIFIED UNDER THREE GROUPS NAMELY: i. Protection causing complete shut down of the unit. ii. Protection causing load reduction of the unit. iii. Protection causing annunciation only.

1.PROTECTIONS CAUSING COMPLETE SHUT DOWN OF THE UNIT. i. Failure of all feed pumps i.e., reserve feed pumps if any fails to start on tripping of

running pumps even after a preset time delay. ii. Boiler shut down due to failure of both FD Fans, all ID Fans and other conditions. iii Reheater protection which is to ensure continuous steam flow through

REHEATER tubes at specified conditions.

2. PROTECTION CAUSING LOAD REDUCTION.

a. ID Fans:Normally 2 ID Fans are sufficient for boiler MCR. If any one of the two running ID

Fans trips, the boiler load shall be run down to60% MCR and action shall be initiated to start the standby ID fan for boiler load greater than 60% MCR.

b. FD Fans.

Any one of the two running FD Fans trip, the boiler load shall be run down to 60% MCR.

c. Mills, PA Fans & Coal feeders:

This reduces the boiler load correspondingly due to limitations in fuel firing capabilities.

3. PROTECTIONS CAUSING ANNUNCIATION:

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The causes that lead to visual/audible annunciation are covered under various sub systems like FSSS, SADC, SB control system, FUEL oil, system, Air & Flue gas system, Steam & Water system etc. These interlocks & protection systems are divided into two portions based on the area they cover as briefly described below.

a. BOILER AUXILIARIES INTERLOCK & PROTECTION.

i) This system takes care of sequence of starting protection and interlock of boiler auxiliaries like FD Fans, ID Fans, AHs, Dampers, Valves etc. covered in this write up.

a. FURNACE SAFEGUARD SUPERVISORY SYSTEM (FSSS).

This system takes care of interlocks required for starting, supervising the operating and safe shut down of the equipments connected with fuel firing system.

BOILER HOUSE AUXILARY INTERLOCKS

1.0 ID FAN INTERLOCKS (FOR TWO FANS)

This Boiler equipped with

* 2 ID Fans * 2 FD Fans * 2 Cold PA Fans * 2 Trisector regenerative AH * 3 Tube mills

1.1. Conditions existing when the unit is shutdown and prior to starting of ID fans.

- ID fan À' and ID fan `B' OFF. - Inlet regulating damper of fans A & B fully open. - Inlet gates of ID fan A & B open. - Outlet gates of ID fans A & B open. - The inlet regulating dampers and VFD speed control will be on manual controls

during shut down and signal from furnace draft control to regulating equipments of ID fans disconnected.

- Lube oil pumps of ID fans OFF

1.2. Starting ID fan À' (ID fan `B' OFF)

a. ID fan À' shall be prohibited from starting till the following conditions are satisfied. - Inlet dampers of ID fan À' in minimum position. - Outlet gate of ID fan À' closed.

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- Inlet gate of ID fan `A' closed. - LUB oil pressure to the ID fan-A bearing adequate. (LUBE oil pressure adequate

lamp indication shall be provided on the control in DCMIS). - ID Fan and Fan motor bearing temperature not very high. - One of the airpreheaters running. - Motor winding temperature not very high. - VFD"Aux. supplies healthy"in ID Fan A channel-1(CH-1) & channel-2 (CH-2). - VFD"Ready" signal from channel-1 (CH-1) OR channel-2 (CH-2) is present. - VFD "Start permissive" from channel-1 (CH-1) OR channel-2 (CH-2) is present. - When ID Fan-A is started (ID Fan B is off), impulse shall be given for: - Opening the inlet gate and outlet gate of ID Fan A simultaneously. - Connecting the Inlet regulating dampers/VFD control of ID Fan A to the auto

control.- Closing the inlet gate and the outlet gate of ID fan B and bringing the regulating

inlet dampers/VFD control minimum position. - Permission to start either FD Fan A or FD Fan B. - VFD Channel-1 (CH-1) "Start". The fan now starts and run at minimum speed. - VFD Channel-2 (CH-2) "Start". This impulse is to be given after fan reaches

minimum speed.

1.3 Starting ID Fan B (ID Fan A is OFF)

Interlocks similar to those at clause 1.2 shall hold good for this condition.

1.4 Tripping of ID Fan A (ID Fan B is OFF)

a. ID Fan-A shall trip automatically under the following conditions. (ID Fan-A trip shall mean that "Stop" impulses shall be issued to channel-1 & channel-2 simultaneously).

- ID Fan A bearing temperature too high (prior to this, ID fan A bearing temperature high shall be annunciated in UCB).

- ID Fan A motor bearing/winding temperature too high (prior to this ID Fan 'A' motor bearing/winding temperature high shall be annunciated in UCB).

- Post purge fan trip from FSSS.

- Vibration level of fan or motor very high (high to be alarmed) after 10 minutes delay.

- ID Fan A motor protection acted.

- ID Fan-A channel-1 (CH-1) & channel-2 (CH-2) input breaker 11kv trip. Here only the respective channel shall be issued a "STOP" impulse.

- "Fault" from channel-1 & channel-2. Here only the respective channels shall be issued stop impulse.

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b. When ID Fan A trips (ID Fan B is OFF) impulses shall be given for:

- Opening the outlet gate of ID Fan B.

- Opening the inlet gate and inlet damper of ID Fan B to wide open position.

- Disconnecting the impulse from auto control system (output from A/M station).

- Opening the inlet dampers/VFD control of ID Fan A to wide-open position. 01

-- Tripping the working FD Fans.

- Boiler tripping. (thro FSSS)

- To keep the inlet gate and outlet gate of ID fan A open.4

1.5 Tripping of ID fan B (ID fan A is OFF)

Interlocks similar to those at clause 1.4 shall be good for this condition.

1.6 Starting of ID fan B (ID fan A is ON) a. ID fan B shall be prohibited from starting unless the following conditions are satisfied:

- Outlet gate of fan B is closed. - Inlet gate of fan B is closed. - Inlet dampers/VFD Control of fan B are in minimum position. - Lube oil pressure to the fan bearing is adequate - Fan and fan motor bearing temperature not very high. - Motor winding temperature not very high. - Both AHs are running. - VFD "AUX. supplies healthy" in ID fan B channel-1 (CH-1) & channel-2 (CH-2). - VFD "Ready"signal from channel-1 (CH-1) OR channel-2 (CH-2) is present. - VFD "Start permissive" from channel-1 (CH-1) OR channel-2 (CH-2) is present.

Note: Lube oil pressure adequate lamp indication shall be provided on the control desk.

b. When ID fan B is started, impulses shall be given for

- Opening the inlet gate and outlet gate of fan B after the motor reaches the rated speed. - Connecting the inlet dampers/VFD of fan B to auto control. - Permissive to start other FD fan. - VFD Channel-1 (CH-1) "Start". The fan now starts and run at minimum speed. - VFD Channel-2 (CH-2) "Start". This impulse is to be given after fan reaches minimum speed.

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1.7 Starting of ID fan A (ID fan B is ON):

Interlocks similar to those at clause 1.6 shall be hold good for this condition.

1.8 Tripping of ID fan B (ID fan A is ON)

a. ID fan B shall trip automatically under the following conditions. (ID fan B trip shall mean that :Stop" impulses shall be issued to channel-1 & channel-2 simultaneously).

- Fan bearing temperature too high (prior to this fan bearing temperature high shall be annunciated in UCB).

- Fan motor bearing/winding temperature too high (prior to this fan motor bearing/winding

temperature high shall be annunciated in UCB). - Vibration level of Fan/motor very high (high to be alarmed) after 10 minutes delay. - ID fan A channel-1 (CH-1) & channel-2 (CH-2) input breaker 11 KV trip. Here only

the respective channel shall be issued a "Stop" impulse. - "Fault" from channel-1 & channel-2. Here only the respective channels shall be

issued stop impulse. - ID Fan-B Motor protection acted. 01 Note: Lube oil pressure low condition will be annunciated.

b. When ID fan B trips (ID fan A is ON) impulses shall be given for:

- Disconnecting the regulator from acting on the inlet dampers. - Bringing the inlet dampers of Fan B to the minimum position. - Closing the inlet gate of fan B. - Closing the outlet gate of fan B. - Tripping the FD fan B, provided FD fan A is ON. - Boiler load shall be reduce to 60% MCR at the rate of 60% MCR/mis.

1.9 Tripping of ID fan A (ID fan B is ON): Interlocks similar to those at clause 1.8 shall hold good for this condition:

Note:

1. Individual start/stop push button will be given in UCB/CRT for each VFD control. 2. For more details refer BHEL-EDN VFD documents.

2.0 FD FAN INTERLOCKS.

2.1 Conditions prior to starting FD Fans:

i. FD FAN-A and FD FAN-B OFF ii. FAN inlet damper to maximum opening.

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iii. Outlet dampers are fully open. iv. FAN inlet damper regulator disconnected. v. Lube oil pumps of FD Fans OFF.

2.2 Starting FD FAN-A (FD FAN- B is OFF):

(a) FD FAN-A shall be prohibited from starting until the following conditions are satisfied.

i. ID FAN-A or ID FAN-B is ON. ii. Control oil pressure adequate (Control oil pressure adequate lamp indication shall be provided on the control desk) iii. FAN-A inlet damper in the minimum position. iv. Outlet damper of FAN-A in closed position. v. FAN / Motor bearing temperature not very high. vi. Motor winding temperature not very high.

(b) When FD FAN-A is started (FD FAN-B is OFF) impulses shall be given for:

i. Outlet damper of FAN-A to open after the motor reaches rated speed. ii. The outlet damper of FD FAN-B to close & inlet damper of FAN-B to be driven to

minimum position. iii. Connecting the inlet damper of FAN - A control drive to auto control.

2.3 Starting of FD FAN-B (FD FAN-A is OFF): Interlocks similar to those at clause 2.2 shall hold good for this condition.

2.4 Tripping of FD FAN A (FD FAN-B is OFF).

(a) FD FAN-A shall trip automatically under the following conditions:

i. FD FAN-A bearing temperature too high (prior to this, FD FAN-A bearing temperature high will be annunciated in UCB.)

ii. FD FAN-A motor bearing / winding temperature too high (prior to this, FD FAN-A motor bearing / winding temperature high will be annunciated in UCB).

iii. Both ID Fans trip.

iv. Post purge Fan trip.

v. Vibration level of FAN-A or Motor bearing very high. (High to be alarmed) after 10 minutes delay.

vi. FD FAN-A lube oil pressure very low (prior to this lube oil pressure low shall be annunciated in UCB.

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vii. FD FAN-A motor protection acted 01

(b) When FD FAN-A trips (FD FAN-B is OFF) impulses shall be given for:

i. Disconnecting the inlet damper control drive from auto control system (output signal from A/M station.)

ii. Bringing the inlet regulating damper of FAN-A to the maximum position. iii. Bringing the inlet regulating damper of FD FAN-B to the maximum position. iv. Opening the outlet damper of FD FAN-B. v. To open the emergency scanner air damper. vi. Boiler tripping vii. The outlet damper of FD FAN-A shall remain open.

2.5 TTripping FD FAN-B (FD FAN-A is OFF):

Interlocks similar to those of clause 2.4 shall hold good for this condition.

2.6 Starting FD FAN-B (FD FAN-A is ON):

(a) FD FAN-B (FD FAN-A is ON) shall be prohibited from starting until the following conditions are satisfied:

i. Both ID Fans are ON. ii. Fan control oil pressure adequate. (Control oil pressure adequate lamp indication

shall be provided on the control desk. 01iii. FAN-B inlet regulating damper in the minimum position. iv. Outlet damper of FAN-B in closed position. v. FAN-B and its motor bearing temperature not very high. vi. Motor winding temperature not very high.

(b) When FD FAN-B is started (FD FAN-A is ON) impulses shall be given for:

i. Opening the outlet damper of FD FAN-B after the motor reaches rated speed. ii. Connecting the impeller control drive of FD FAN-B to auto control.

2.7 Starting FD FAN-A (FD FAN-B is ON):


2.8 Tripping of FD FAN-B (FD FAN-A is ON):

a) FD FAN-B shall trip when FD FAN-A is ON under the following conditions:

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i. ID fan B trips.

ii. FD FAN-B motor bearing /winding temperature too high (prior to this, FD FAN-B motor bearing/winding temperature high shall be annunciated in UCB).

iii. FD FAN-B bearing temperature too high (prior to this, FD FAN-B bearing temperature high shall be annunciated in UCB).

iv. Vibration level of FAN -B bearing very high. (High to be alarmed) after 10 minutes delay.

v. FD FAN-B lube oil pressure very low(prior to this lube oil pressure low shall be annunciated in UCB).

vi. FD FAN-B motor protection acted. 01

(b) WWhen FD FAN-B trips (FD FAN A is ON), impulses shall be given for:

i. Disconnecting regulator impulse from acting on inlet damper control drive of FAN-B.

ii. Bringing impeller of FAN-B to the minimum position. iii. Closing the outlet damper of FAN-B. iv. Energisation of partial load relay to reduce boiler load to 60% MCR. v. Tripping mills working more than four elevations through FSSS

2.9. Tripping of FD FAN -A (FD FAN-B is ON):


3.0 PA fan Interlocks:

3.1 Conditions prior to start up - PA fan A and PA fan B off - Outlet dampers of fan A and B closed - Regulating damper of fan A and fan B in closed position - Regulating damper is disconnected.

3.2 Starting PA fan A (PA fan B OFF) a) PA fan A shall be prohibited from starting until the following conditions are satisfied:

- Regulating vanes of PA Fan A in the minimum position. - Outlet gate of PA fan A in closed position - Anyone FD fan is ON - Purge complete - PA fan A and fan motor bearing temperature not very high - PA fan A motor winding temperature not very high 01 - PA fan A lub. Oil pressure adequqate 01

Note : Signal from PA fan A start PB shall simultaneously go to start PA fan A and seal air fan A .

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b) When PA fan A is started (PA fan B is OFF), impulses shall be given for: The starting of PA fan A shall be done in the following sequence

- Release regulating damper control to auto. - Opening the outlet gate of PA fan A after the motor reaches rated speed. - Bringing the regulating damper of PA fan B to the minimum position - Closing the outlet gate of PA fan B - Permission to start any Mill / Three coal elevations through FSSS

3.3 Starting PA fan B (PA fan A is OFF) Interlocks similar to those at clause 3.2 shall hold good for this condition. 3.4 PA fan A shall trip (PA fan B is OFF)

a) PA fan A shall trip (PA fan B is OFF) under the following conditions: - PA fan A bearing temperature too high (prior to this bearing temperature high shall

be annunciated in UCB) - PA fan A motor bearing /winding temperature too high (prior to this, motor

bearing/winding temperature high shall be annunciated in UCB) - Vibration level of Fan or motor very high (High to be alarmed) after 10 minutes

delay. - Boiler trips - PA fan A motor protection

b) When PA fan A trips (PA fan B is OFF), impulses shall be given for: - Disconnecting the regulating damper of PA fan A from auto control - Bringing the regulating damper of PA fan A to the minimum position - Closing the outlet gate of PA fan A - Tripping all the working Mills / coal elevations (done through FSSS) - Bringing the regulating damper of PA fan B to the minimum position 01

3.5 Tripping PA fan B (PA fan A is OFF) Interlocks similar to those at clause 3.4 shall hold good for this condition. 3.6 Starting PA fan B (PA fan A is ON)

a) PA fan B shall be prohibited from starting unless the following conditions are satisfied: - Any one FD fan is ON

- Regulating damper of PA Fan B in the minimum position

- Outlet gate of PA fan B in closed position.

- PA fan B and fan motor bearing temperature not very high.

- PA fan B motor winding temperature not very high. 01- PA fan B lub. Oil pressure adequqate . 01

b) When PA fan B is started (PA fan A is ON), impulses shall be given for:

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- Opening the outlet gate of PA fan B after the motor reaches rated speed - Connecting the regulating vanes of PA fan B to auto control - Permission to start Mill / Three coal elevation through FSSS.

3.7 Starting PA fan A (PA fan B is ON)


3.8 Tripping of PA fan B (PA fan A is ON)

a) PA fan B shall trip (PA fan A is ON) under the following conditions:

- PA fan B bearing temperature too high (prior to this, fan bearing temperature high shall be annunciated in UCB)

- PA fan B motor bearing / winding temperature too high ((prior to this, fan motor bearing winding temperature high shall be annunciated in UCB)

- Boiler Trips - Vibration level of fan or motors very high (high to be alarmed) after 10 minutes

delay. - PA fan B motor protection acted

b) When PA fan B trips (PA fan A is ON), impulses shall be given for: - Disconnecting the regulating damper control of PA fan B from auto control - Bringing the regulating damper of PA fan B to minimum position - Closing the outlet gate of PA fan B

- Energisation of partial load relay (load to be limited to 60 MCR)

3.9 Tripping of PA fan A (PA fan B is ON) Interlocks similar to those at clause 3.8 shall hold good for this condition. 3.10 Both the PA fans shall trip simultaneously when any boiler trip condition is present (Impulses from FSSS)4.0 AH interlocks:

4.1 Conditions before start up of AHs:

i. Both AHs are OFF (Electric motor and air motors are OFF) ii. The inlet dampers and the outlet dampers in the Gas path, Secondary Air bypass dampers, AH secondary air outlet damper are in full open condition.

4.2 Starting AH - A (AH-B is OFF):

i. AH-A main electric motor is started if the sump oil temperature of the bearing measured through RTD is less 70 Deg.c.

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ii. Whenever AH-A electric motor trips, impulse shall be given for starting AH-A air motor by De-energising the solenoid, provided & the sump oil temperature of support/guide bearing of is less than 70 Deg.c. iii. Impulse shall be given for closing of the inlet and outlet dampers of AH-B which is OFF.

4.3 Tripping of AH-A (AH-B is OFF). i. Whenever the sump oil temperature of support/guide bearing is greater than

70 Deg.c an alarm shall be initiated through RTD to alert the operator. The operator shall check the circulation pump operation and the coolant flow at local to bring down the sump oil temperature. In case if the temperature of sump oil is unable to be brought down AH electric motor/air motor shall be tripped manually.

ii. Air motor shall trip automatically when the electric motor of AH-A starts.

Note: Trip signal of AH is to be taken from proximity switch if provided. (Sensing stoppage of AH motor) or electric motor trip and air pressure for air motor low.

4.4 Starting of AH-B (AH-A is OFF):The interlocks said above for AH-A starting (AH-B OFF ) clause 4.2 is applicable here.

4.5 Tripping of AH-B (AH-A is OFF). The interlocks said above for AH-A tripping (AH B OFF ) clause 4.3 is applicable here.4.6 Both AHs are working when AH-A trips & AH-B continues to run:

The gas inlet damper, the secondary air outlet damper and primary air outlet damper of the tripped AH shall automatically closed. The gas outlet damper and the secondary air inlet damper of the tripped AH need not be closed. However, if the operator wants to manually close these dampers they can be closed. The operator shall try for restarting the tripped AH-A by either air motor or electric motor. If the restarting is not possible the boiler load shall be brought down to 60%.

4.7 Both AHs are working when AH-B trips & AH -A continues to run: The interlocking conditions said above under 4.6 is applicable here.

4.8 Both AHs are tripped: If both AH- A & AH-B trip the operator may try for restarting the AHs. If anyone of the AH is not started within 5 minutes the operator shall manually trip the boiler.

4.9 Interlocks for oil circulation pumps of support bearing:

(Applicable for AH-A and AH-B) 2 x 100% oil circulation pump have been provided for the support bearing. Anyone of the two oil circulation pumps can be pre-selected as main pump and the other as standby.

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4.10 Following interlocks shall be provided for oil circulation pumps. (Applicable for Air heater A and Air heater B) 2 x 100% oil circulation pump have been

provided for the support bearing. Anyone of the two oil circulation pumps can be pre-selected as main pump and the other as standby. Following interlocks shall be provided for oil circulation pumps.

i. Whenever the sump oil temperature of support bearing of AH-A is high (40 Deg. C) impulse shall be given to start the main oil circulation.

ii. The standby oil circulation pump shall start when the main oil circulation pump fails

to start or trips. iii. The main oil circulation pump/standby oil circulation pump shall trip when the

temperature of the support bearing falls below a preset value (40 Deg.c). iv. Manual operation of the lube oil pumps shall be prohibited when the ambient

temperature is too low. Since viscosity of the oil will be high the pump could not be started.

4.11 Interlocks for oil circulation pumps of guide bearing: 2x 100% oil circulation pumps have been provided for guide bearing. Anyone of the two oil circulation pumps can be pre-selected as main pump and the other as standby. The interlocks for these pumps shall be similar to those for support bearing as envisaged in clause 4.10. The set point for starting the lube oil pump of the guide bearing is 40 Deg.c.

5.0 BLOW DOWN VALVE: (VALVE TAG NO: B095 & B096)

i. When DRUM water level rises to 125 mm above normal water level an annunciation DRUM LEVEL high shall be given in UCB.

ii. When drum level rises to 125 mm above normal water level, blow down valves shall open and this condition shall be annunciated.

iii. Blow down valves shall close automatically when the water level falls down to NWL. One de interlock switch shall be provided for both the valves for manual operation.

6.0 INTERLOCKS FOR FD FAN LUBRICATING OIL SYSTEM:

6.1 FD FAN-A lube oil system: (Ref. Drg. No. :-2-00-107-21361/00)

i. Pump A will start automatically if pump B trips provided A/M switch is in auto position. ii. Pump A will start automatically with a time delay of 0-60 seconds if lube oil pressure falls below a set value and the pump B is working provided A/M switch

is in auto position. iii. Pump B will start automatically if pump A trips/has not started provided A/M

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switch is in auto position. Pump B will start automatically with a time delay of 0- 60 seconds if lube oil pressure falls below a set value and the pump A is working provided A/M switch is in auto position.

iv. Pump A or pump B can be started/tripped by pressing the respective local push button only when A/M switch is in manual position.

v. FD FAN A shall be prohibited from starting until the control oil Pressure is adequate

Note : FD fan A lube. oil pressure LOW shall be alarmed in UCB.

6.2 FD FAN B lubricating oil systems: (Ref. Drg. No. 2-00-107-21361/00)

Interlocks similar to those at 6.1 above shall hold good for FD FAN-B lubricating oil system.

6.3 Interlock for PA FAN A & B lubricating oil system:- (Ref. Drg. No. 2-00-107-21363/00)

Interlocks similar to 6.1 shall hold good for PA FAN A&B lube oil system.

6.4 Interlock for ID FAN A&B lube oil system:- (Ref. Drg. No. 2-00-107-21362/00)

Interlock similar to 6.1 shall hold good for ID FAN lube oil system.

7.0 FURNACE TEMPERATURE PROBE

i. Furnace temperature probe can be advanced / retracted using the push buttons Provided in UCB (part of DCS) as well as from local. ii. Furnace temperature probe shall be prohibited from being advanced further into the furnace if furnace temperature sensed by it is more than 540 Deg.c.(Contact

divided in DDCMIS) iii. If furnace temperature probe is inside the furnace and the temperature exceeds 540 Deg.c it will be retracted back automatically.

8.0 MISCELLANEOUS INTERLOCKS:

8.1 Interlocks and protection write-up for DDI gate/dampers with motor operated blowers / isolation valves.

8.1.0 Guillotine gate with motor operated blower & manual isolation valve for blower:

i. Gate will close and open according to BHA interlock and protection. ii. Blower shall be continuously working irrespective of whether the gate is in close

or open position, when boiler is working.

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Drg. NO.: 4-97-096-90874 /01


Note: The blower motor for ID FAN outlet gate shall be started simultaneously with ID FAN.

iii. Blower shall be continuously working irrespective of whether one of the ID FAN is in operation or not.

iv. The manual isolation valve in the blower line shall always be open. v. If the blower motor trips due to overload, it shall be annunciated.

8.1.1. Interlocks for guillotine gate without blowers but with manual isolation valve:

i. Manual valve has to be kept open irrespective of the position of the gate.

8.2.0 Interlocks for motor operated valves with BY PASS valves:

i. First open the BY PASS valve fully. ii. After main valve is fully opened, BY PASS valve may or may not be closed.

iii. Main valve can be closed wherever required. The BY PASS valve, if not already closed, can be closed when main valve is commanded to close

8.3.0 Interlocks for valves with integral BY PASS: ( as applicable )

i. Isolating valves before and after the feed regulating valves. ii. Isolating valves before & after hp heater in the boiler feed water line.

iii. Isolating valves on BY PASS of feed water of HP heaters. iv. Isolating valves on main steam line at Superheater outlet.

8.40 The above valves shall have the following interlocks:

i. The main valve shall not open unless its motorized integral BY PASS valve is in fully open position.

ii. The motorized integral BY PASS valve shall close simultaneously when its main valve is closed.

9.0 Motor operated valve interlock requirements

i. TOA design valves: ii. For gate valves upto and including 100 mm (4 inch), globe valves and regulating

Valves.

Valve closing: Actuator motor tripping shall be done by torque switch. Limit switch shall not be used in the control circuit for tripping.

Valve opening: Actuator motor tripping shall be done by limit switch. Torque switch shall be used

as a backup in the control circuit.

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TRICHIRAPALLI



Drg. NO.: 4-97-096-90874 /01


GATE VALVES ABOVE 100 MM:

Valve closing / opening:

Actuator motor tripping shall be done by limit switch. Torque switch shall be used in the control as a back up.

Non TOA Design VALVES:

Valve closing: Actuator motor tripping shall be done by torque switch. Limit switch shall not be used the control circuit for tripping.

Valve opening: Actuator motor tripping shall be done by limit switch. Torque switch shall be used in the control circuit as a back up.

10.0 REHEATER PROTECTION LOGIC:

REHEATER protection shall be provided as part of BHA interlock and protection system. This protection is provided to protect the REHEATER against starvation of steam flow during abnormal conditions. To take care of REHEATER protection, the boiler shall be tripped after 10 seconds, when any of the following conditions occur:

1) When boiler is working and if

i. Generator circuit breakers open. ii. HP BYPASS or LP BYPASS valves remain closed less than 2%. 01

2) When boiler is working and if

i. Turbine trips. ii. ss HP BYPASS or LP BYPASS valves remain closed less than 2% 01

Copy of recommended Reheater protection logic is enclosed. (ANNEXUREA) 01

*****

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PROJECT: NEW PARLI - TPP,UNIT- 1, 1X250MW,CUST. NO:0361, BCR NO:590 MEASUREMENT AND CONTROL RECOMMENDATIONS FOR AIR AND FLUE GAS PATH

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1 HLB 10&20 CY101 & 102 VT FD FAN-A & B MOTOR BRG.- NDE VIBRATION METAL 4 -- -- -- -- 50 --

OC -- -- -- -- D,I,A.N6.3/9.9 -- mm / Sec -- --

BENTLY NEVADA LLC,USA

-- --- -- -- T 03 BHA INTERLOCKS

2 HLB 10&20 CT 101 TEFD FAN-A & B MOTOR BRG.-NDE TEMPERATURE METAL 2 -- -- -- -- 50 --

OC -- -- -- -- -- D,I,A.NT+5/ T+10 --

OC -- -- -- -- --- -- -- R 01 BHA INTERLOCKS

3 HLB 10&20 CT 301 TIFD FAN-A & B MOTOR NDE BRG. TEMPERATURE METAL 2 -- -- -- -- 50 --

OC -- -- -- -- -- L,I -- OC -- -- -- -- --- -- -- R 00

4 HLB 10&20

CT 102 TO 113

TE FD FAN-A &B MOTOR WINDING TEMPERATURE

METAL 24 -- -- -- -- 50 -- OC -- -- -- -- -- D,I,A.N125/ 130

-- OC -- -- -- -- --- -- -- R 00 BHA INTERLOCKS

5 HLB 10&20 CY103 & 104 VT FD FAN-A & B MOTOR BRG.- DE VIBRATION METAL 4 -- -- -- -- 50 --

OC -- -- -- -- -- D,I,A.N6.3/9.9 -- mm / Sec -- --



6 HLB 10&20 CT 114 TEFD FAN-A & B MOTOR BRG.- DE TEMPERATURE METAL 2 -- -- -- -- 50 --

OC -- -- -- -- -- D,I,A.NT+5/ T+10 --


7 HLB 10&20 CT 302 TI FD FAN-A & B MOTOR DE BRG.TEMPERATURE METAL 2 -- -- -- -- 50 --OC -- -- -- -- -- L,I -- OC -- -- -- -- --- -- -- R 00

8 HLB 10&20 CT115 to 117 TE FD FAN-A & B BRG.- TEMPERATURE METAL 6 -- -- -- -- 50 --

OC -- -- -- -- -- D,I,A.N90/ 105 --


9 HLB 10&20 CY105 & 106 VT FD FAN- A & B BRG.- VIBRATION METAL 4 -- -- -- -- 50 --

OC -- -- -- -- -- D,I,A.N6.3/ 12.6 -- mm / Sec -- --



10 HLB 10&20 CT303 to 305 TI FD FAN-A & B BRG. - TEMPERATURE METAL 6 -- -- -- -- 50 --

OC -- -- -- -- -- L,I -- -- OC -- -- -- -- --- -- -- R 00

11 HLB 10&20 CP 401 PP FD FAN SUCTION PRESS. SEC AIR 2 -- -24 -- mmWC 27 50OC -- -- -- -- -- T -- -- OC -- -- -- --

4-97-288-90779 -- -- -- 00

12 HLA 10&20 CP 101 PT FD FAN-A & B OUTLET PRESSURE SEC AIR 22600 X 2800 328 -- mmWC 30 53

OC -- -- -- -- -- D,I, -- -- -- -- -- -- --4-97-288-

90779 -- -- P 00

13 HLA 10&20 CP401&402 PP FD FAN-A & B OUTLET PRESSURE SEC AIR 4

2600 X 2800 328 -- mmWC 30 53

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90779 -- -- -- 00

14 HLA 10&20 CT401&402 TP FD FAN-A & B OUTLET TEMPERATURE SEC AIR 4

2600 X 2800 328 -- mmWC 30 53

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90780 -- -- -- 02

15 HLA 10&20 CP 403 PP AH - A & B INLET PRESSURE SEC AIR 22600 X 2600 302 -- mmWC 30 100

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90779 -- -- -- 00

16 HLA 10&20 CP 102 PT AH - A & B INLET PRESSURE SEC AIR 22600 X 2600 302 -- mmWC 30 100

OC -- -- -- -- -- D,I, -- -- -- -- -- -- --4-97-288-

90779 -- -- P 00

17 HLA 10&20 CT403 to 408 TP AH-A & B INLET TEMPERATURE SEC AIR 12

2600 X 2600 302 -- mmWC 30 100

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90780 -- -- -- 00

18 HLA 10&20 CT 101 TE AH-A & B INLET TEMPERATURE SEC AIR 22600 X 2600 302 -- mmWC 30 100

OC -- -- -- 13 -- D,I -- -- -- -- -- -- --4-97-288-

90780 -- -- P 03

19 HHL 10&20 CT401 to 406 TP AH -A OUTLET TEMPERATURE SEC AIR 12

3500 X 2300 164 -- mmWC 321 325

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90780 -- -- -- 00

20 HHL 10&20 CP 401 PP AH - A OUTLET PRESSURE SEC AIR 23500 X 2300 164 -- mmWC 321 325

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90779 -- -- -- 00

21 HHL 10&20 CT101 to 104 TE AH-A & B OUTLET TEMPERATURE SEC AIR 8

3500 X 2300 164 -- mmWC 321 325

OC -- -- -- 20 -- D,I -- -- -- -- -- -- --4-97-288-

90780 -- -- P 03

22 HHL 10&20 CP 101 PT AH - A & B OUTLET PRESSURE SEC AIR 23500 X 2300 164 -- mmWC 321 325

OC -- -- -- -- -- D,I -- -- -- -- -- -- --4-97-288-

90779 -- -- P 00

23 HHL 10&20 CF101 & 102 FT AT AEROFOIL - FLOW SEC AIR 4

3000 X 2750 140 -- mmWC 321 325

OC 1195 -- T/HR -- -- D,I,C -- -- -- -- -- -- -- 1/2" SW -- P 00 AIR FLOW CONTROL-

24 HHL 10&20 CT105 & 106 TE AEROFOIL OUTLET TEMPERATURE SEC AIR 4

3000 X 2750 140 -- mmWC 321 325

OC -- -- -- 10 -- D,I,C -- -- -- -- -- -- --4-97-288-

90780 -- -- P 03 TEMP. COMPENSATION

25 HHL 10&20 CP 402 PP AEROFOIL OUTLET PRESSURE SEC AIR 23000 X 2750 164 -- mmWC 321 325

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90779 -- -- -- 00

26 HHL 15&25 CP401 & 402 PP WIND BOX PRESSURE - L & R SEC AIR 4 -- 100 -- mmWC 321 325

OC -- -- -- -- -- T -- -- -- -- -- -- --4-97-288-

90779 -- -- -- 00

27 HHL 15&25 CP 101 PT WIND BOX PRESSURE - L & R SEC AIR 2 -- 100 -- mmWC 321 325OC -- -- -- -- -- D,I -- -- -- -- -- -- --

4-97-288-90779 -- -- P 00

PARLINSTDRG.NO.3-97-288-92118/03

PAGE 2 OF 7

21447000361 PARLI VOL D1T01-47

21447000361 PARLI VOL D1T01-47

PROJECT: NEW PARLI - TPP,UNIT- 1, 1X250MW,CUST. NO:0361, BCR NO:590 MEASUREMENT AND CONTROL RECOMMENDATIONS FOR AIR AND FLUE GAS PATH

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c & i Checklist

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