Attachment #8 - SPP Grid Code

SPP Grid Code

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Preface

EGAT’s requirements for connection of Small Power Producer (SPP) generating unit and its connection facility to the Grid (Grid Code) consist of technical criteria of generating unit, connection facility, planned outages; coordination of operational planning and scope of technical responsibilities of EGAT and SPP including other necessary criteria for unit dispatching and unit shutdown for maintenance outage.

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SPP Grid Code

1. Definition 2. Required Information prior to Connection to the Grid

3. Coordination Procedures

3.1 Coordination Prodedure for Maintenance 3.2 Production Plan 3.3 Safety Coordination 3.4 Operational Procedure during Emergency in the Power System 3.5 Quality of Supply 3.6 Other Requirements 4. Operational Planning

4.1 Monthly Plan 4.2 Additionaly Monthly Plan 4.3 Monthly Production

5. Communication 6. Amendment of SPP Grid Code

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1. Definition

Outage means an outage which SPP requests to shut down the generating

unit or reduce its output capacity for inspection, maintenance of the generating unit or equipment or the connection facility, which are under the responsibility of SPP. The outage can be classified as: a) Planned Outage, which the unit shutdown is planned and scheduled

yearly, b) Maintenance Outage, which the unit shut down is not included in the

Planned Outage, but notified in advance as defined in 3.1.6 and 3.1.7 Quality of Supply means quality of supply of the power system that EGAT

controls and maintains according to the contract with its customers and the quality of supply that SPP shall control and maintain in accordance with the requirements specified in 3.5 for connecting to the Grid. Moreover, the SPP generating unit shall meet all criteria as specified in the Quality of Supply. Emergency Event means an event which EGAT cannot control and maintain

the power system in its normal operating condition including: a) Event that causes power frequency to be higher than 50.75 Hz or lower

than 49.25 Hz. b) Event that causes over or under voltage at the connection point

exceeding +/- 10 percent of the normal value. During this abnormal condition, the voltage at that location may drop to 0 KV for a period of half cycle to a few seconds due to either start up of large motor/load or fault in the power system until that abnormal condition is solved.

c) Event that causes over load in transmission lines. Maintenance Cycle means a maintenance schedule of SPP power plant

through out its life, which SPP shall provide and submit to EGAT prior to the commercial operation date. This plan shall specify clearly detail and types of maintenance including maintenance periods. The number of years for Major Overhaul shall not exceed 2 in each 4-year cycle. Moreover, in case the Major Overhaul is performed every 2 years in the 4-year cycle, the total number of maintenance days shall not exceed 80 days within that 2-year period. For the year that the Major Overhaul takes place, the maintenance period shall not exceed 45 days. 3-Year Planned Outage Program means an outage schedule of the planned maintenance for calendar years 1 to 3 according to the Maintenance Cycle, which SPP shall provide and submit to EGAT in advance. In case of any changes, the SPP shall give a notice to EGAT of the monthly planned outage. However, in case the number of Major Overhauls exceeds the number specified in the approved Maintenance Cycle, SPP is allowed to perform the

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extra Major Overhaul only during this period when the reason for this extra Major Overhaul is caused by EGAT. 2. Required Information prior to Connection to the Grid

In order to maintain EGAT’s power system reliability, the SPP shall submit detail of connection facility to connect its generating unit to the Grid to EGAT for their approval. The information shall include parameters of each generating unit, details of connection facility from power plant to the connection point. The required information shall be as follows: a) Generator

Type □round rotor □salient pole

Number of Poles Speed (RPM) kV Rating MW Rating KVA Rating Armature Amp. (A) Armature Voltages (kV) Field Currents (A) Exciter Voltages (V) Power Factor Capability Curve

b) Generator Parameters for Dynamic Simulation

H = inertia constant of the machine D = Damping constant of the machine Xd = direct-axis reactance X’d = direct-axis transient reactance X’’d = direct-axis subtransient reactance Xq = quadrature-axis reactance X’q = quadrature-axis transient reactance X’’q = quadrature-axis subtransient reactance Xl = leakage reactance T’do = direct-axis open circuit transient time constant T’’do = direct-axis open circuit subtransient time constant T’qo = quadrature-axis open circuit transient time constant T’’qo = quadrature-axis open circuit subtransient time constant S (1.0) = saturation factor at 1.0 p.u. terminal voltage S (1.2) = saturation factor at 1.2 p.u. terminal voltage

c) Block diagram of turbine governor and excitation system showing

parameters in IEEE Standard d) Unit transformer rating/features/name plates

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e) Type of primary fuel and back up fuel (if available) f) Data of connection facility

Design voltage Conductor size Type of insulator Var compensator

- MVar of capacitor

- MVar of shunt reactor g) Other equipment data that may not meet the specified criteria at the

connection point.

3. Coordination Procedures 3.1 Coordination Procedures for Maintenance

3.1.1 Objectives

For good coordination of energy production between EGAT and SPP, EGAT has defined procedures and detail of how SPP should submit their information and the maintenance outage period of the power plants and connection facility to EGAT so that EGAT can consider the planned outage together with the others in order that the power system is stable and it can maintain Power Quality Requirements (3.5.1) and sufficient spinning reserve during the outage. 3.1.2 Maintenance Cycle Notification

SPP must submit its Maintenance Cycle and 3-Year Planned Outage Program, which include dates and times of the outages to EGAT at least 30 days before the commercial operation date. After receiving the notification, EGAT must reply/give approval of the Maintenance Cycle and the 3-Year Planned Outage Program to SPP within 15 days. Upon approval of the Maintenance Cycle, SPP shall follow these planned outages through out the power plant life. 3.1.3 3-Year Planned Outage Notification

Every year, before the first day of October, SPP must notify their anticipated 3-Year Planned Outage Program, as defined in 3.1.2, to EGAT. The following detail must be included:

a) Available capacity for EGAT, b) Shut down periods and the number of generating units to be

shut down, and c) Alternative periods, if the periods in b) cannot be approved by

EGAT.

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If SPP has no intention to revise the 3-Year Planned Outage Program, SPP is requested to confirm the plan to EGAT. 3.1.4 EGAT’s Approval of Yearly Planned Outage Before the first day of November, EGAT must inform SPP of its approval of 3-Year Planned Outage Program based on power demand and other relevant factors that would impact the system stability. EGAT will make endeavor to accommodate every SPP unit shutdown on the proposed date; however, if the planned outage cannot be scheduled on proposed date, EGAT will propose other appropriate date to SPP for its consideration. If SPP finds that EGAT’s proposed date is not possible, SPP must contact EGAT to reconsider scheduling of the date together before the fifteenth day of November based on the system stability.

3.1.5 Monthly Planned Outage

After EGAT has approved the Yearly Planned Outage, if SPP cannot, in any month within the planned outage under 3.1.4, shut down its generating unit on the agreed dates, SPP must inform EGAT, not less than 30 days before the previously approved outage date as defined in 3.1.4, of the new schedule and reasons for postponement or cancellation. Nevertheless, postponement will not change the shutdown period; if the period is longer than what was planned according to 3.1.4, this outage will be considered as Weekly Planned Outage defined in 3.1.6. After EGAT has received the revised schedule from SPP, EGAT will consider/approve the revised Monthly Planned Outage based on the system stability. If EGAT does not approve the revised schedule but SPP insists to shut down its generating unit; SPP can shut down its generating unit as indicated in the revised schedule. However EGAT will count those shut down period as the addition to the Yearly Planned Outage. If SPP notifies the revised schedule to EGAT less than 30 days, EGAT will follow the planned outage as submitted under 3.1.4 3.1.6 Weekly Planned Outage In case SPP must shut down the generating unit for maintenance outage for a period longer than 24 hours in addition to the Yearly Planned Outage, SPP must notify EGAT 7 days before the maintenance outage. This will allow EGAT with sufficient time to economically dispatch generating units in the system and maintain the system stability based on the planned maintenance of the transmission lines or other limitations.

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If SPP notifies EGAT less than 7 days, which gives EGAT insufficient time, EGAT will consider this as short-notice. EGAT will accept, without any penalties, the short-notice not more than three times a year. SPP, who has submitted the short-notice more than three times a year, will be penalized by counting 1.5 hours, instead of 1 hour, for each 1 hour shut down period in order to compensate for EGAT's losses.

If SPP informs EGAT of maintenance outage of a period less than 24 hours during peak and partial peak periods, but later requests again for additional maintenance outage during peak and partial peak period in the following day, EGAT will consider this additional maintenance outage to be longer than 24 hours and count the outage as the short-notice. 3.1.7 Daily Planned Outage

If SPP needs to shut down its generating unit for maintenance outage of a period less than 24 hour, SPP must notify the maintenance outage in the available capacity report to EGAT before 12:00 hr of the day on which SPP will shut down its generating unit. This is to allow EGAT, with sufficient time, to economically dispatch generating units with minimum impact of production cost of electricity and the system spinning reserve. EGAT will consider this maintenance outage period as normal shut down hours. However, if SPP notifies the maintenance outage of the generating unit later than 12:00 hr, EGAT will not count as the maintenance outage hour.

If the submission date of the planned outage specified in 3.1.3 to 3.1.7 falls on EGAT's non-working day, SPP must submit the plan one working day earlier. If SPP needs to shut down its generating unit for additional maintenance outage, SPP must notify EGAT one day earlier before 12:00 hour for shutting down its generating unit.

3.2 Production Plan

3.2.1 Yearly Production Plan Every year before the 1st day of October, SPP must submit to EGAT the expected available capacity and energy to be dispatched to EGAT for each month from January to December of the following year. The Plan must follow the approved Maintenance Cycle. 3.2.2 Monthly Operational Planning Before the 15th day of the month, SPP that uses commercial fuel or renewable energy (biomass), for electricity production must notify their next monthly production plan and available energy to EGAT.

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3.3 Safety Coordination

For any maintenance, requested by EGAT and/or SPP, which may affect the safety rules of the power system or safety of personal or properties of another party, the party that will perform the maintenance must notify another party as soon as possible. It must be informed at least 24 hours in advance, so that necessary precautions can be taken by another party. If it will impact energy dispatching to EGAT and selling to customers, the party who initiates the event must provide detail of the maintenance and set up a meeting with concerned parties in order to set up measures to prevent damages to the power system, equipment, lives, and properties.

3.4 Operational Procedure during Emergency in the Power System

SPP's generating unit is not required to stabilize system frequency through EGAT's automatic generation control; therefore SPP must support the power system during emergency as follows: 3.4.1 If the system frequency is out of the 49.25 to 50.75 Hz range, and EGAT's Dispatching Control Center does not make any contact to SPP, SPP must assist the system by increasing or decreasing production respectively to stabilize the system frequency at 50 Hz. During this period, SPP will be exempted from the contractual obligations defined in the Power Purchase Agreement. 3.4.2 If the system frequency is under 48.00 Hz, or over 51.00 Hz, for more than one minute, SPP can trip its generating unit without penalties. 3.4.3 If the frequency is under 47.90 Hz, or over 51.10 Hz, SPP can disconnect its generating unit from the Grid without penalties.

3.5 Quality of Supply EGAT has defined the standard for Quality of Supply for EGAT's customers; therefore, SPP must design its generator and auxiliary equipment to withstand the system conditions and comply with the standard defined by EGAT. Moreover, SPP' generator must not cause the Quality of Supply to the unacceptable level as defined in the standard. 3.5.1 Power Quality Requirements

3.5.1.1 Voltage at Connection Point

- In the EGAT's system, the voltage is regulated at ± 5% of nominal voltage under normal condition, and it may vary up to ±10% under abnormal condition.

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- In PEA'S system, the voltage is regulated at ± 5% of nominal voltage and it may vary up to ± 10% under abnormal condition.

- In MEA's system, the Quality of Supply depends on the voltage levels as follows:

Condition 115 kV 69 kV 24 kV 12 kV

Normal -1.74%, +2.61% 113.0 -118.0 kV

-1.74%, +2.90% 67.0 -71.0 kV

-1.91%, -1.67% 21.8 -23.6 kV

-0.96%, -1.67% 10.9 -11.8 kV

Emergency -1.74%, +6.96% 113.0 -123.0 kV

-1.74%, +5.07% 67.0 -72.5 kV

-2.09%, 0.00% 21.6 -24.0 kV

-1.04%,0.00% 10.8 -12.0 kV

3.5.1.2 The system frequency is maintained at 50 ± 0.5 Hz during normal condition, except abnormal or emergency conditions. 3.5.1.3 For voltage and current distortion, EGAT requires customers having non-linear load to control their harmonic distortion within the defined levels in order not to affect any other customers. Limit of each order of harmonic voltage distortion and the voltage distortion (Vt) in percent at connection points are defined in the table below.

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Harmonic current distortion limits (Arms) of each order, that customer must prevent such current to flow into the system as defined by EGAT are shown in the table below. Harmonic Current Limit for Customers at Connection Points

The deviation of 10% or 0.5 Amp, whichever is greater, is allowed to be used with each order (but not more than two orders).

If the Lowest MVASC at the connection point is different from MKASC (Base) defined in the table, the limit of harmonic current is defined by the following equation;

3.5.1.4 For the customers that their equipment or processes can cause voltage flickering must control the voltage flickering with in the following limit:

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Pst = The value used for assessment of the severity of short-term voltage flickering (10 minutes)

where m depends on the source of the voltage flickering. The followings are the suggested values for m. m = 4, for equipment such as furnaces m = 3, for most equipment that can cause voltage flickering but is less likely to operate simultaneously m = 2, for equipment that is more likely to operate simultaneously m = 1, for equipment that is operate simultaneously Plt = The value used for assessment of the severity of long-term voltage flickering (2 - 3 hours)

where N is the number of measurements of Pst during a measurement period, which is normally 2 hours and therefore N = 12.

3.5.2 Power Quality Standard for Power Plants Connected to the Grid 3.5.2.1 SPP must maintain the frequency within the range as defined in 3.5.1.1 and 3.5.1.2 3.5.2.2 SPP must be able to import or export reactive power at 0.85 leading and lagging power factor to maintain voltage at the connection point, and/or as to import or export reactive power to the power system at each period. 3.5.2.3 SPP must keep the voltage distortion, at the connection point within the limit defined in 3.5.1.3. 3.5.2.4 SPP must reduce harmonic current flow into Grid at the connection point by controlling the harmonic current that generated from equipment of SPP's customers to be within the limit defined in 3.5.1.3.

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3.5.2.5 SPP must try to reduce the severity level due to voltage flickering caused by equipment or production or process either from SPP or SPP customer at connection points defined in 3.5.1.4.

3.5.3 In case the voltage distortion and harmonic current are higher

than those defined in 3.5.2.3 and 3.5.2.4 respectively and they are being checked and corrected by EGAT, SPP must endeavor to keep those values close to the limit such that they will not damage equipment owned by either EGAT or EGAT’s customers or SPP.

3.5.4 If EGAT finds that SPP cannot control its Power Quality defined

in 3.5.2, SPP must correct them urgently and propose plan to improve its Power Quality to EGAT.

3.5.5 SPP must request EGAT to provide the Power Quality

Requirements at the connection point and uses these requirements as basis for the design.

3.6 Other Requirements

3.6.1 SPP must not change the power system by changing or increasing the capacity of the generating unit, or synchronizing additional generating unit, or doing anything that would affect Power Quality without EGAT's consent.

3.6.2 EGAT has the right not to allow synchronization of SPP’s

generating unit if:

3.6.2.1 SPP cannot comply with standards of Power Quality defined in 3.5 after EGAT has notified such a non-compliance with reasonable time; 3.6.2.2 SPP has violated synchronization regulation of SPP generating unit.

3.6.3 SPP will be responsible for synchronization of the generating

unit to the Grid and always need permission before synchronization so that EGAT can maintain the proper spinning reserve of the system.

3.6.4 In case where SPP does not follow conditions in the power

purchasing agreement or other agreements which have no impact to the system stability, EGAT reserves the right to notify SPP such that SPP can correct its action in accordance with the agreement.

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4. Operational Planning

4.1 Monthly Plan

Within the 4th week of each month, EGAT will issue a monthly dispatching plan in advance to SPP so that SPP can use them as the guideline for operational planning. The purchasing plan includes capacity that will be dispatched in each period during weekdays, weekends, and holidays, all of which are according to the power purchasing agreement. This purchasing plan will be used for the whole month.

4.2 Additional Monthly Plan

In case when EGAT or SPP need to adjust their agreed Monthly Plan, the party, who needs the adjustment, must notify another party immediately and revise the Monthly Plan together. This revised Monthly Plan will be followed through out the month. The adjustment initiated by SPP must not violate the maintenance requirements defined in 3.1.

4.3 Monthly Production

Within the first week of each month, SPP must report its production in the previous month for each generating unit. The report will be kept as references for national load forecast. The report must include: a) Hourly gross MW production every day and installed capacity b) Monthly energy production and sales

- Gross energy production - Energy sales to all customers - Energy for station service, and - Energy sales to EGAT.

5. Communication

During normal operation, communication is done verbally via telephones or party line. Any load dispatching, which will affect electricity tariff calculation, will be communicated by fax. The sender must sign his/her name of the sending document. The recipient must sign his/her name to acknowledge receipt of the document and fax the document back to the sender for reference. If communication via fax is not possible, both parties must use voice recorders, or other means which both parties has previously agreed, to record their conversations. In the conversion, both parties must state their names, time, and events. These are to be kept as evidences. Capacity and energy production are recorded via the energy meter which both parties can access the data through telemetering and use the recorded values for