A

TRAINING REPORT

AT

132 KV SUBSTATION

JIND (NEW)

(24 July 2010 to 21 August 2010)

Submitted to: Submitted by:

Mr. Jugal Kishor Vikash Singh (0805809903)

(H.O.D. of ELE Dept.) Branch ELE

SCR Polytechnic Gohiyan Jind (Haryana)

FOREWORD

I was required to undergo on four weeks training during the July 2010

to September 2010 towards the partial fulfillment of my diploma Being a

student of Electrical Engineering. I choose to undertake this training at an

Electrical Engineering, since it is a highly progressive sector these days, and

the demand for power is on a rise. Therefore, I landed up at 132 KV

substation Jind one of the good substation in Northern India and a fine

source of Electric power distribution for the local areas The training was a

great learning experience and I have tried to put what I learnt, through these

pages.

PREFACE

Electricity is one of the most convenient and important source of energy

electricity is used at home and in industry for various purposes such as

lighting, heating operating machine and so on.

Therefore, generation of electricity holds important place in our

society. The generation of electricity and its per capita consumption is an

index to the prosperity of a nation. Man has found a no. of ways to generate

electricity. He began by tapping the energy generated by chemical reaction

for e.g., in a Daniel cell. However, this form was suitable only for very small

application. In addition, large amount of electricity could not be generated

using this method and the output voltage was not suitable. Therefore, man

sought new ways of electric power generation. In this question he invented

huge power plants. The early plants used wood to generate steam for water,

which in term used to drive an electric generation. However, this quick

depletion of forests led man to look for alternative source of power. The

power of falling water was used to generate electricity. However, a need was

felt for more power generation. In addition, the Hydel-power station was

costlier and tougher to establish, even though the cost of operations was

lower consequently, in the mid twentieth century, coal was found to be a

technologically and economically viable option for steam power generation.

Today, most of the world's electric energy needs are met using coal

Nevertheless, the progress can never stop. Even this cheap alternative has

some limitation. The greatest problem is that of ash disposal. A huge amount

of ash is generated in a coal-based station and it is highly harmful for man

and his environment. Therefore, must of the new power station coming up in

India are natural gas based. According to some experts, for sustainable

development because of its low long-term availability can only be a

transition fuel. Indeed, hydrogen is stipulated to be the fuel of the future.

Clearly, the electric power requirement of man kind is on rise and therefore

the need of looking at alternate and unconventional source of energy is being

best. There are a no. of such sources, for instance, solar, geothermal, tidal

wind etc. these source, though not sufficient all by themselves, can

contribute significantly to our power needs.

As such the consistent growth of power is vital to meet our day-to-

day- requirements and improve the living standards.

ACKNOWLEDGEMENT

We as a group would like to express our heart filled gratitude to the various

People those who have he pad us curing the entire training period. First of all

We would spastically like to extend a word of thanks to J.E. Mr.Jyoti

Sharma, Haryana Vidyut Para saran Nigam limited 132KV substation, Jind.

It was under his able guidance and leadership that we are permitted to be a

Part of this esteemed substation.

We also would like to thanks ALM Mr.Rajbir Nain & Mr. Virender Kundu

(SA), of the substation for their Instrumental in guiding us to the various

Processes in the substation and Thus played vital role in enriching our

Knowledge in the technical field.

CONTENTS

1. Introduction to HPGCL

2. Introduction to substation JIND

3. Switchyard

Lightening Arrestor Capacitor Voltage Transformer Wave trap Current Transformer (CT) Potential Transformer (PT) Circuit Breaker Isolators Insulator Buses Power Transformer Neutral Current Transformer

4. Power line Carrier Communication (PLCC)

5. Battery Room

6. Control Room

7. Substation Auxiliaries Supply

8. Earthing of Substation

INTRODUCTIO N TO HPGCL

Haryana Power Generation Corporation Limited (HPGCL) was incorporated as a company under companies Act 1956on 17th March 1997 and certificate for commencement of business was granted on 5th August 1997. The business of generation of power of erstwhile Haryana State Electrically Board was transferred to Haryana Power Generation Corporation Limited on 14th August 1998 pursuant to the implementation of power reforms in the state of Haryana. The main objective of HPGCL is to generate power in the state of Haryana from the existing station in most efficient manner on commercial lines and shell whole of the power generated exclusively to Haryana Vidyut Parasaran Nigam Limited and to setup new power project on the state sector.

The main objectives of HPGCL are as under:

1. To generate power from its existing Generating Stations in the most efficient manner on commercial lines and to sell the same to

distribution companies.2. To setup new power generation projects. 3. from June 2005 HPGCL is also responsible for the work of power

trading i.e. Procurement of power on long term and short term basis, signing of power purchase agreements with power producers/traders

SUBSTATION (JIND )

Haryana Vidyut Power Generation Corporation Limited (HVPNL) 132 KV substation Jind is an undertaking of Haryana Power Generation Corporation Limited Panchkula (HPGCL). Substation serve as a source of energy supply for the local areas of distribution in which these are located. Their main functions are to receive energy transmitted at high voltage from the generating stations, reduce the voltage to a value appropriate for local distribution and provide facilities for switching.

It is established near milk plant on HANSI road, JIND. This substation required area of 15 acres. The input of the substation is mainly from three substations which are as follows:

1. 132 KV from JHANJ2. 132 KV from PANIPAT3. 132 KV from SAFIDON

Then this input power is stepped down and passes to the nearest substation. So the output of this substation is also going to the three substations which are as follows:

1. 132 KV to JIND (OLD)2. 132 KV to KHERI

SWITCHYARD

Haryana Vidyut Power Generation Corporation Limited (HVPNL) 132 KV

switchyard JIND is an undertaking of Haryana Power Generation (HPGCL)

Corporation Limited Panchkula (HPGCL). Switchyard serve as a source of

energy supply for the local areas of distribution in which these are located.

Their main functions are to receive energy transmitted at high voltage from

the generating stations, reduce the voltage to a value appropriate for local

distribution and provide facilities for switching.

A Highlight of Switchyard Of substation is given in Table Below:

LIGHTNING ARRESTER

The lightning arrester as a surge diverter is used for the protection of power system against the high voltage surges. It is connected between the line and earths and so diverts the incoming high voltage wave to the earth. Lightning arrester act as safety valves designed to discharge electrical surges resulting from lightening strokes, switching or other disturbances, which would other wise flash over insulator or puncture insulation, resulting in a line voltage and possible failure of equipment. They are designed to absorb enough transient energy to prevent dangerous reflection and to cut off the flow of power frequency follow (or dynamic) current at the first current zero after the discharge of transient. They include one or more sets of gaps to establish the breakdown voltage, aid in interrupting the power follow current, and prevent any follow of current under normal condition(except that gap shunting resistor when used ton assume equal distribution of voltage across the gap, permits a very small leakage current). Either resistance element to limit the power follow current of values the gap can interrupt, or an additional arc extinguishing chamber of interrupt the power follow current are connected in series with gaps. Arresters have a short time lag of breakdown compared with the insulation of apparatus, the breakdown voltage nearly independent of the steepness of the wave front.

Lightning protection by means of lightning arrestors and gaps and overhead ground wire is a mean of reducing outages and preventing damage to station equipments from lightning disturbances.

The ground wire or earthling screen does not provide protection against the high voltage wave reaching the terminal equipment, so some protective devices are necessary to provide protection of power stations, substation and transmission line against the voltage wave reaching there. The most common device used for the protection of power system against the high voltage surge is sure diverter.

CAPACITOR VOLTAGE TRANSFORMER

A capacitor voltage transformer (CVT) is a transformer used in power system to step down extra high voltage signal and provide low voltage signals either for measurement or to operate a protective relay. In its basic form the device consist of three parts: two capacitor across which the voltage signals is split, an inductive element to tune the device to the supply frequency and a transformer used to isolate and further step down the voltage for the instrumentation and protective relay. The device has at least four terminals, a high voltage terminal to connection to the high voltage signal, a ground terminal and at least one set of secondary terminals for the connection of the instrumentation and the protective relay. CVTs are typically single phase devices used for measuring voltage in excess of one hundred kilovolts where the use of voltage transformer would e uneconomical. In practice the first capacitor, C1, is often replaced by a stack of capacitor connected in series. This result in large voltage drop across the stacks of capacitors that replaced the first capacitor and a comparatively small voltage drop across the second capacitor C2, and hence the secondary terminals.

WAVETRAP

Wave trap is a parallel tuned inductor – capacitor ‘tank’ Circuit made to be resonant at the desired communication frequency. It is the effort to utilize the same transmission line between two substations for the purpose of communications. At these communication frequencies the tank ckt provides high impedance and does not allow passing through them & onto the substation bus & into transformers.

 The Line trap offers high impedance to the high frequency communication signals thus obstructs the flow of these signals in to the substation bus bars. If there were not to be there, then signal loss is more and communication will be ineffective/probably impossible.

CURRENT TRANSFORMER

These instrument transformers are connected in ac power circuits to feed the current coil of indicating and metering instrument (ammeter, wattmeter, and watt hour’s meter) protective relays. Thus the CTs broaden the limit of measurements and maintain a watch over the current flowing in the circuit and over the power loads. In high voltage installation CTs in addition to above, also insolate the indicating and metering instruments from high voltage. The current transformer basically consists of an iron core on which arc wound a primary and one or two secondary windings. The primary is directly inserted in the power circuit (the circuit in which the current is to be measured) and ton the secondary winding or windings the indicating and metering instruments and relays are connected. When the rated current of CT flows through its primary winding a current of 5 amperes will appears in its secondary windings. The primary windings are single turn windings and the number of turns on secondary winding depends upon the power circuit current to be measured. The larger current to be measured, more the number of turns on secondary. The ratio of primary current to the secondary current is known as the transformation ration.

POTENTIAL TRANSFORMER (PT)

The potential transformer are employed for voltage above 380 volts to feed the potential coils of indicating and metering instrument (voltmeter,Wattmeter, and watt hour’s meter) and relays. These transformers make the ordinary low voltage instrument suitable for measurement of high voltage and isolate them from high voltage.The primary windings of the potential transformer is connected to the main bus bar of the switchgear installation and to the secondary windings, various indicating and metering instrument and relays are connected.When rate high voltage is applied to the primary of PT the voltage of 10V appear at the secondary windings. The ration of rated primary voltage to the rated secondary voltage is known as turn or transformation ration.

CIRCUIT BREAKER

A circuit breaker is a mechanical device designed to close or open contact members, thus closing or opening an electrical circuit under normal or abnormal conditions. It is so designed that it can be operate manually under normal condition or automatically under faulty condition. An automatic circuit breaker is equipped with a trip coil connected to a relay or other means designed to open or break automatically under abnormal condition, such as over current. When the circuit breaker is closed considerably energy stored in the springs. The connects are held together by means of toggles. To open the circuit breaker only a small pressure is required to be applied on the trigger. When t6hw trigger is actuated by the protective relay, it trips and potential energy of the springs is released and the contacts open in the fraction of second.

HIGH VOLTAGE CIRCUIT BREAKER

High voltage circuit breakers are broadly classified by the medium used to extinguish the arc.

Oil filled (dead tank and liver tank) Oil filled, minimum oil volume Air blast SF6 Vacuum circuit breaker (manufacturing in ABB, AREVA, cutler-

hammer (Eaton), Siemens, Toshiba…)

High voltage circuit breakers are routinely available up to 765 KV AC.

Live tank circuit breaker are where the enclosure that contains the breaking mechanism is at line potential, that is, “live”. Dead tank circuit breaker enclosures are at earth potential.

[Interrupting principle of high voltage circuit breakers

Current interruption in high voltage circuit breaker is obtained by separating two contacts in a medium, such as SF6 having excellent dielectrical and arc quenching properties.

SULPHUR HEXAFLUORIDE (SF6) CIRCUIT BREAKER

In many type of circuit breakers the extinguishing force built up relatively slowly after the moment of contact separation, and hence arc is extinguishing after a few half cycles current have passed zero. The prevention of arc re-igintioin needs a high dielectrical strength of the arc path and its fast recovery current zero. In the case of high voltage circuit breaker these properties are particularly required to have quick arc extinction and have less time for quick recovery voltage build up. Vacuum circuit breaker and Sf6 circuit breaker have better properties in this regard compared to conventional bulk oil minimum oil as well as air blast circuit breakers hence modern trend is to employ vacuum circuit breaker and SF6 circuit breakers in HV system.Modern circuit breaker employs heavy gas SF6 as the medium for quenching the arc. Sf6 gas because its excellent dielectric, arc quenching, chemical and other physical properties, has proved it’s superiority over other mediums such as oil or air for use in circuit breakers. Several types of SF6 circuit breakers have been developed by different manufacturers during last two decades for rated voltages 3.6 to 760 Kv.

Rated voltage 245 KVFrequency 50 HZCurrent 200 AOpening voltage 220 V DCTotal wt. 2400 KGGas wt. 21 WGInclude gas SF6Pressure 16.5 KG/cmgShort circuit 40 KV -3 sec.Made by Siemens, India

ISOLATOR

Isolator (or disconnect switches) are not equipped with arc quenching device and, therefore, not used to open circuits carrying current. As the name implies isolator isolates one portion of the circuit from another and is not intended to be opened while current is flowing. Isolators must not be opened until the circuit is interrupted by some other means. If an isolator is opened carelessly, when carrying a high current, the resulting arc could easily cause a flash over the earth. This may shatter the supporting insulator and may even cause a fatal accident to the operator, particularly in high voltage circuits. While closing a circuit, the isolator is closing first, then the circuit breaker. Isolators are necessary on supply side of circuit breaker in order to ensure isolation (disconnection) of the circuit breaker from the live parts for the purpose of maintenance.

INSULATOR

The porcelain insulators employed in substations are of the post and busing type. They sever as supports and insulation of the bus-bars.A post insulator consists of porcelain body, cast iron cap and flanged cast iron base, as shown in fig. the hole in the cap is threaded so that the bus-bar are either directly bolted to the cap or fixed by means of bus-bar clamp. Post insulators are available with round oval and square flanged bases for fixing respectively, with aid of one, two or four bolts. Each base in addition also has an earthing bolt. A bushing insulator consists of porcelain-shell body ,upper and lower locating washers used for fixing the position of the bus bar in shell, and mounting flange with holes drilled for fixing bolts and supplied with an earthing bolt, as shown in fig. For current rating above 2,000A, the bushings are designed to allow the main bus bars to be passed directly through them. Each phase of the bus bars is located with paint according to a fixed color code red, yellow and blue so that phase of main bus bars can be identified. But at Jind substation disk type insulators are used which is shown in fig.

BUS-BARS

Bus bar term is used for a main bar or conductor carrying an electric current to which many connections may be made.

Bus bars are merely convenient means of connecting switches and other equipment in to various arrangements .the usual arrangement of connections in most of the substations permits working on almost any piece of equipment without interruption to incoming or outgoing feeders.

In some arrangement two buses are provided two which the incoming or outgoing feeder and the principal equipment may be connected. One bus is usually called the main bus and the other auxiliary or transfer bus. The main bus may have a more elaborate system of measuring instruments, relay etc.associated with it. The switches used for connecting feeders or equipment to one bus or the other are called transfer switches.

POWER TRANSFORMER

Power transformer are used for stepping-up the voltage for transmission at generating stations and for stepping-down voltage for further distribution at main step down transformer substation. Usually naturally cooled, oil immersed, known as ON type, two winding, three transformers are used up to the rating of 10 MVA. The transformers of rating higher than 10MVA are usually cooled. For very high rating, the forced oil, water cooling and air blast cooling may be used. For regulating they voltage of transformers used are provided with on load tap changer. They are put in operation during load hours and disconnect during light load hours i.e. they are usually operated at approximately full load. This is possible because they are arranged in blank and can be thrown in parallel with other units or disconnect at will. So power transformers are designed to have maximum efficiency at or near full load (i.e. with iron loss to full load copper loss ratio of 1:1). Power transformer are designed to have considerable leakage reactance then is permissible in distribution transformer because in power transformers inherent voltage regulation is not as much important as current limiting of the higher leakage reactance. At 132 KV substation Jind two transformers are used for the stepping down purpose. Each of them is of 100 MVA. These transformers steps down the voltage 132 KV into 33 KV. This voltage is then transmitted to the 33 KV substations of KHERI

NEUTRAL CURRENT TRANSFORMER

This transformer is used after the power transformer. This transformer is a safety device. If there is any extra current in the transformer then this current is taken by the neutral current transformer and this current is grounded by the transformer. This is connected to the power transformer for grounding the extra current. If there is any type of current that current will be grounded by the neutral current transformer.

CONTROL ROOMS

The control room (or the operating room) is the nerve center of the power station. The various control performed from here are voltage adjustment, load control, emergency tripping of turbines etc. and the equipment and instruments housed in a control room are synchronizing equipment, voltage regulators, relays, ammeters, voltmeters, watt meters, KWh meters, kVARh meters, temperature gauges, water level indicator and other appliances, as well as a mimic diagram and suitable indicating equipment to show the opened or closed position of circuit breaker, isolators etc. the location of control room in relation to other section of the power station is also very important. It should be located away from the sources of noise and it should be near the switch house so as to save multi-core cables Used for interconnections. Of course, if there is any fire in switch house, the control room should remain unaffected. Also there is an access from the control room to the turbine house. The control room should be neat and clean, well ventilated, well lighted and free from draughts. There should be no glare and the color scheme should be soothing to eyes. The instrument should have scales clearly marked and properly calibrated and all the apparatus and circuit should be labeled so that they are clearly visible.

BATTERY ROOM

All power plant and substation require dc power supply for protection and control purposes and dc supply is obtained from secondary or storage batteries. Battery room is the heart of a substation. Lead acid batteries are most commonly used in po0wer stations and substations because of their high cell voltage and lower cost.Station batteries are assembled of a certain number of accumulator cells depending on the operating voltage if the respective de circuits. Storage batteries are of two type’s viz lead acid and alkaline batteries. Lead acid batteries are most commonly used in power stations and substations because of their higher cell voltage and low cost. At substation 132KV Jind 110 cells are used each of 2 volts. And nickel cadmium alkaline batteries are used.

TRANSMISSION TOWER

MATERIAL USED IN LINE CONDUCTORS

Aluminum conductor steel reinforced (or ACSR) cable is a specific type of high capacity, high strength standard cable used in overhead power lines. The outer standards are aluminum, chosen for its excellent conductivity, low weight, and low cost. The centre strand is of steel, providing extra strength. Simultaneously however, the tower electrical conductivity of the steel core has only a minimum effect on the overall current carrying capacity of the cable. Due to a skin effect, most of the current is carried by the outer, aluminum portion of the cable, so the higher Resistance of the inner, steel strand is largely immaterial.

POWER LINE CARRIER COMMUNICATION (PLCC)

Power line carrier communication (PLCC) is mainly used for telecommunication, tele-protection and tele-monitoring between electrical substations through power lines at high voltages, such as 110 Kv, 220 Kv, 400 Kv. PLCC integrates the transmission of communication signal and 50/60 Hz power signal through the same electric power cable. The major benefit is the union of two important applications in a single system.

In a PLCC system the communication is established through the power line. The audio frequency is carried by a carrier frequency and the range of carrier frequency is from 50 kHz to 500 kHz. The modulation generally used in these systems is amplitude modulation. The carrier frequency range is allocated to include the audio signal, protection and the pilot frequency. The pilot frequency is a signal in the audio range that is transmitted continuously for failure detection.

The voice signal is converted/compressed into the 300 Hz to 4000 Hz range, and this audio frequency is mixed with the carrier frequency. The carrier frequency is again filtered, amplified and transmitted. The transmission of these HF carrier frequencies will be in the range of 0 to +32db. This range is set according to the distance between substations.

PLCC can be used for interconnecting PBXs. The electricity board in India has an internal network PLCC between PBXs.

Contents 1 Line trap 2 Coupling capacitor 3 Line matching unit 4 Digital power line carrier

LINE TRAP

It is also called “Wave trap”. It is connected in series with the power (transmission) line. It blocks the high frequency carrier waves (24 kHz to 500 kHz) and let power waves (50 Hz – 60 Hz) to pass through. It is basically an inductor of rating in mili henry.

COUPLING CAPACITOR

It provides low impedance path for carrier energy to HV line and blocks the power frequency circuit by being a high impedance path.

LINE MATCHING UNIT

LMU is a composite unit consisting of Drain Coil, Isolation transformer with Lightning Arrester on its both the sides, a Tuning Device and an earth switch. Tuning Device is the combination of R-L-C circuits which act as filter circuit. LMU is also known as Coupling Device. Together with coupling capacitor, LMU serves the purpose of connecting effectively the Audio/Radio frequency signals to either transmission line or PLC terminal and protection of the PLCC unit from the over voltages caused due to transients on power system.

DIGITAL POWER LINE CARRIER

A power line carrier using a power line as transmission media needs to change its transmission system from analog to digital to address rapid diffusion of IP devices and digital telecommunication devices. With this view, digital power line carrier (DPLC) was developed featuring several technological measures which enable digital transmission via power lines and performed a field evaluation test. As a result, DPLC has the required quality of bit error rate characteristics and transmission ability such as transmitting information from monitored electric-supply stations and images.

SUBSTATION AUXILIARIES SUPPLY

In small unattended substation only a small amount of power for electric lighting during regular periods of inspection, maintenance and repair is required. In regional substation the electric power is required for the auxiliaries:- the lighting circuit, air blast fan of transformer, battery charging sets oil servicing facilities, compressor unit in case of air blast circuit breakers, ventilating fans of the substation buildings water supply and heating system equipment etc. substation incorporating synchronous condensers the supply is also required for the operation of auxiliaries equipment of the synchronous condensers.At 132 KV substation Jind a stepping down transformer is used which step down 33 KV into 11 KV which is used for the substation auxiliaries’ supply. Feeders are also taken from this voltage.

EARTHING OF SUBSTATION

The term earthing mean connecting of the non current carrying parts of the electrical equipment or the neutral point of the supply system to the general mass of the earth in such a way that at all times am immediate discharge of electrical energy take place without a danger. The earthing is provided by the following activities:-

1. for the safety of personnel form of electrical shock- insuring that non current carrying parts, such as equipment frames are always safely at ground potential even though insulation fails.

2. For the safety of equipment and personnel against lightning and voltage surges- providing the discharge path for the lightning arresters, gaps and similar devices.

3. For providing the ground connection for ground neutral system.4. For provide a mean of positively discharging or highly de-

energizing feeders or equipment before proceeding with maintenance of them. The station earthing system should have low resistance.

Grounding of power system is highly important. A substational and adequate ground that will not burn off or permit danger rise in voltage under abnormal conditions essential. Equipment earthing also help in the earth fault protection.Solid grounding will be done it means a direct connection of the neutral to the earth.