UPPCL SUMMER TRAINING REPORT PDF
A SUMMER TRAINING REPORT ON UTTAR PRADESH POWER of Uttar Pradesh Power Corporation Ltd. (UPPCL) on January 14, line. ppt on summer training on uppcl. 1. DEPARTMENT OF ELECTRONICS ENGINEERING INSTITUTE OF ENGINEERING & TECHNOLOGY. summer training report on unnao sub station - Free download as Word Doc .doc) , PDF File .pdf), Download as DOC, PDF, TXT or read online from Scribd UPPCL. Uploaded by. Yogendra Katiyar · Training Report in a k.v Substation .
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A Summer Internship Report At Uttar Pradesh Power Corporation Limited ( UPPCL) On “TRANSMISSION IN KV SUB-STATION” In the fulfillment of the fifth. LIST OF ABBREVIATIONS GIS: Gas Insulated Switchgear SLD: Single Line Diagram LA: Lightening Arrester BPI: Bus Pole Insulator CVT: Capacitor Voltage. A REPORT. ON. “SUMMER TRAINING”. Undertaken at. / kV. Substation at. Bhinmal. (Jalore). Under the guidance of. Er. K. C. Gupta (executive engineer .
It is important in PLCC. It connects remote r substations without the help of telecom company. At the end of each feeder there are two WT are installed Connecting phase will be same for all feeders. IEC Type of Cooling: HV- Operating principle: The circuit diagram has been given in the transformer circuit. It works on the principle of electro-magnectic induction evident. It senses two temperature of Auto Transformer- a.
Mineral insulating oil, Low Viscisity. Insulating Grade: A Type: Balmer- Larwie. HV — This transformer is used to provide AC power supply in the substation. The output of this transformer has 3 phase 4 wire star connection. These transformers are connected- a.
At the 33 kV outlet of auto Transformer b. Gas Filled: N2 nitrogen Rated voltage: GCB is basically a switch which can interrupt circuit when fault current flows or when power flows in reverse direction. As the switching is done under N2 gas environment, the arcing is limited and does not damages equipment. It protects the conventional transformer from fault current.
Maximum system voltage: Insulation level: IVT steps down voltage as its secondary winding has only one turn. This stepped down voltage is a virtual image of its primary voltage. It is used — a.
To reduce line voltage to a value which is suitable for standard measuring. To isolate measuring instruments, relays etc. From direct high voltage. To sense any abnormalities in the voltage. IVT should be connected in parallel with supply line b. Highest system voltage: CT steps down primary current to a measureable value, by means electro-magnetic induction. Current in secondary circuit is directly proportional to primary current.
The secondary current is measured by meters or it operates relay to trip a CB when abnormal current flows in the circuit. All the secondary terminal should be shorted when CT is not in use and or before disconnecting burden. DBR System voltage: F voltage: This disconnecting device can be operated manually.
When abnormal current appears in circuit, it operates automatically electromagnetically and isolate GCB from circuit.
All the conductors found in the site can be devided into two categories. Conductor Bundeled Insulated Conductor Conductor i. Bundeled Conductor Overhead transmission transm: All the overhead conductors are bundeled, i.
A typical standard conductor cross section is- a. The overhead transmission lines are standard and bundled to prevent Corona loss, when surface potential gradient of a conductor exceeds dielectric strength of the surrounding air. By adding more wires instead of solid one, the surface area increases which decreases surface potential gradient. Thus Corona loss prevented. In all overhead connection. Insulated Conductor: Power cable connection- 1. Control cable bears dc signal from DC distribution board to various control element.
Inside Control Room and cable Trench. Fire Fighting Pump: It is a part of safety measures taken at the substation to prevent fire in the main Transformer. It pumps water to the pipes wound at the outside of transformer. Various Tests that are Performed in a Substation: Polarity test: Insulation test: The tests are a.
Primary and secondary injection check 4. Tan Delta test of CVT 5. Earth resistance test-The ground resistance should be as minimum as possible. For kV system it should not exceed 0. Conventional Transformers-Tesla Electric.
DG-Kirloskar Ltd. LCC panel-Scheinder Electric. Disconnector-Switchgear and Structural ltd. F Pump-Marathon Electric. In general, they represent an interface between different levels or sections of the power system, with the capability to switch or reconfigure the connections among various transmission and distribution lines. The major stations include a control room from which operations are coordinated.
Smaller distribution substations follow the same principle of receiving power at higher voltage on one side and sending out a number of distribution feeders at lower voltage on the other, but they serve a more limited local area and are generally unstaffed.
The central component of the substation is the transformer, as it provides the effective in enface between the high- and low-voltage parts of the system. Other crucial components are circuit breakers and switches. Breakers serve as protective devices that open automatically in the event of a fault, that is, when a protective relay indicates excessive current due to some abnormal condition.
Switches are control devices that can be opened or closed deliberately to establish or break a connection. An important difference between circuit breakers and switches is that breakers are designed to interrupt abnormally high currents as they occur only in those very situations for which circuit protection is needed , whereas regular switches are designed to be operable under normal currents. Breakers are placed on both the high- and low-voltage side of transformers.
Finally, substations may also include capacitor banks to provide voltage support. Here in this s. Related Papers. By Irfan jamil. VOL V-Electrical. By Prabir Datta. By Amber Bdr. Power System Engineering. A circuit breaker is an equipment, which can open or close a circuit under normal as well as fault condition. These circuit breaker breaks for a fault which can damage other instrument in the station.
It is so designed that it can be operated manually or by remote control under normal conditions and automatically under fault condition. There are mainly two types of circuit breakers used for any substations. They are a SF6 circuit breakers b Spring circuit breakers For the latter operation a relay which is used with a C.
For still higher voltage, air blast vacuum or SF6 cut breaker are used. The use of SF6 circuit breaker is mainly in the substations which are having high input kv input, say above kv and more.
The gas is put inside the circuit breaker by force i. When if the gas gets decreases there is a motor connected to the circuit breaker. The motor starts operating if the gas went lower than There is a meter connected to the breaker so that it can be manually seen if the gas goes low. The circuit breaker uses the SF6 gas to reduce the torque produce in it due to any fault in the line.
The circuit breaker has a direct link with the instruments in the station, when any fault occur alarm bell rings. A protective relay is a device that detects the fault and initiates the operation of the C. The relay detects the abnormal condition in the electrical circuit by constantly measuring the electrical quantities, which are different under normal and fault condition.
The electrical quantities which may change under fault condition are voltage, current, frequency and phase angle. Having detect the fault, the relay operate to close the trip circuit of CB. The line in Sub-station operate at high voltage and carry current of thousands of amperes. The measuring instrument and protective devices are designed for low voltage generally V and current about 5A. Therefore, they will not work satisfactory if mounted directly on the power lines.
This difficulty is overcome by installing Instrument transformer, on the power lines. There are two types of instrument transformer- 1.
Current Transformer: A current transformer is essentially a step-down transformer which steps-down the current in a known ratio, the primary of this transformer consist of one or more turn of thick wire connected in series with the line, the secondary consist of thick wire connected in series with line having large number of turn of fine wire and provides for measuring instrument, and relay a current which is a constant faction of the current in the line.
Current transformers are basically used to take the readings of the currents entering the substation.
This transformer steps down the current from amps to 1amp. This is done because we have no instrument for measuring of such a large current. The main use of his transformer is: Potential Transformer: It is essentially a step — down transformer and step down the voltage in known ratio. The primary of these transformer consist of a large number of turn of fine wire connected across the line.
The A capacitor voltage transformer CVT is a transformer used in power systems to step-down extra high voltage signals and provide low voltage signals either for measurement or to operate a protective relay. In its most basic form the device consists of three parts: The device has at least four terminals, a high-voltage terminal for connection to the high voltage signal, a ground terminal and at least one set of secondary terminals for connection to the instrumentation or protective relay.
CVTs are typically single-phase devices used for measuring voltages in excess of one hundred kilovolts where the use of voltage transformers would be uneconomical. In practice the first capacitor, C1, is often replaced by a stack of capacitors connected in series. This results in a large voltage drop across the stack of capacitors that replaced the first capacitor and a comparatively small voltage drop across the second capacitor,C2, and hence the secondary terminals.
There are several metering and indicating Instrument e. Ammeters, Volt-meters, energy meter etc. The instrument transformers are invariably used with them for satisfactory operation. In addition to above, there may be following equipment in a Substation: There are four transformers in the incoming feeders so that the four lines are step down at the same time.
In case of a KV or more KV line station auto transformers are used. While in case of lower KV line such as less than KV line double winding transformers are used Auto transformer.
Transformer is static equipment which converts electrical energy from one voltage to another. As the system voltage goes up, the techniques to be used for the Design, Construction, Installation, Operation and Maintenance also become more and more critical. If proper care is exercised in the installation, maintenance and condition monitoring of the transformer, it can give the user trouble free service throughout the expected life of equipment which of the order of years.
Hence, it is very essential that the personnel associated with the installation, operation or maintenance of the transformer is through with the instructions provided by the manufacture diverted around the protected insulation in most cases to earth.
Auto transformer: Hence, it is very essential that the personnel associated with the installation operation or maintenance of the transformer is through with the instructions provided by the manufacture.
Basic principles: The transformer is based on two principles: Changing the current in the primary coil changes the magnetic flux that is developed. The changing magnetic flux induces a voltage in the secondary coil.
It is a device that transfers electrical energy from one circuit to another through inductively coupled conductors — the transformer's coils. Except for air-core transformers, the conductors are commonly wound around a single iron-rich core, or around separate but magnetically - coupled cores. A varying current in the first or "primary" winding creates a varying magnetic field in the core or cores of the transformer.
This varying magnetic field induces a varying electromotive force EMF or "voltage" in the "secondary" winding. This effect is called mutual induction. If a load is connected to the secondary, an electric current will flow in the secondary winding and electrical energy will flow from the primary circuit through the transformer to the load.
In an ideal transformer, the induced voltage in the secondary winding VS is in proportion to the By appropriate selection of the ratio of turns, a transformer thus allows an alternating current AC voltage to be "stepped up" by making NS greater than NP, or "stepped down" by making NS less than NP.
Transformers come in a range of sizes from a thumbnail-sized coupling transformer hidden inside a stage microphone to huge units weighing hundreds of tons used to interconnect portions of national power grids. All operate with the same basic principles, although the range of designs is wide.
While new technologies have eliminated the need for transformers in some electronic circuits, transformers are still found in nearly all electronic devices designed for household "mains" voltage.
Transformers are essential for high voltage power transmission, which makes long distance transmission economically practical.
Pole -mounted single-phase transformer with center-tapped secondary. Note use of the grounded conductor as one leg of the primary feeder. Induction law: The voltage induced across the secondary coil may be calculated from Faraday's law of induction, which states that: If the turns of the coil are oriented perpendicular to the magnetic field lines, the flux is the product of the magnetic field strength B and the area A through which it cuts.
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The area is constant, being equal to the cross-sectional area of the transformer core, whereas the magnetic field varies with time according to the excitation. The simplified description above neglects several practical factors, in particular the primary current required to establish a magnetic field in the core, and the contribution to the field due to current in the secondary circuit. Models of an ideal transformer typically assume a core of negligible reluctance with two windings of zero resistance, when a voltage is applied to the primary winding, a small current flows, driving flux around the magnetic circuit of the core.
The current required to create the flux is termed the magnetizing current; since the ideal core has been assumed to have near-zero reluctance, the magnetizing current is negligible, although still required to create the magnetic field.
The changing magnetic field induces an electromotive force EMF across each winding. Since the ideal windings have no impedance, they have no associated voltage drop, and so the voltage VP and VS measured at the terminals of the transformer, are equal to the corresponding EMFs. This is due to Lenz's law which states that the induction of EMF would always be such that it will oppose development of any such change in magnetic field.
To discharge the switching and lightening voltage surges to earth. Wave trap is an instrument using for tripping of the wave. The function of this trap is that it traps the unwanted waves.
Its function is of trapping wave. Its shape is like a drum.
It is connected to the main incoming feeder so that it can trap the waves which may be dangerous to the instruments here in the substation. As these feeders enter the station they are to pass through various instruments. The instruments have their usual functioning. They are as follows in the single line diagram: The line diagram of the substation: It means the transformer transforms the low voltage into high voltage and high voltage into low voltage at same frequency.
It works on the principle of static induction principle. When the energy transformed into higher voltage, the transformer is called step up transformer but in case of other is known as step down transformer.
Further, Transformerclassifiedin two types: This contrasts with other materials, semiconductors and conductors, which conduct electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors.
A perfect insulator does not exist, because even insulators contain small numbers of mobile charges charge carriers which can carry current. In addition, all insulators become electrically conductive when a sufficiently large voltage is applied that the electric field tears electrons away from the atoms. This is known as the breakdown voltage of an insulator.
Some materials such as glass, paper and Teflon, which have high resistivity, are very good electrical insulators. A much larger class of materials, even though they may have lower bulk resistivity, are still good enough to prevent significant current from flowing at normally used voltages, and thus are employed as insulation for electrical wiring and cables.
Examples include rubber-like polymers and most plastics. Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation.
The term insulator is also used more specifically to refer to insulating supports used to attach electric power distribution or transmission lines to utility poles and transmission towers.
They support the weight of the suspended wires without allowing the current to flow through the tower to ground. During the flash over, the huge heat produced by arching, causes puncher in insulator body. For successful utilization, this material should have some specific properties as listed below: Two types of insulating material are mainly used: Porcelain in most commonly used material for over head insulator in present days.
The porcelain is aluminium silicate. The aluminium silicate is mixed with plastic kaolin, feldspar and quartz to obtain final hard and glazed porcelain insulator material. The surface of the insulator should be glazed enough so that water should not be traced on it.
Now days glass insulator has become popular in transmission and distribution system. Annealed tough glass is used for insulating purpose. Fig; glass insulator Advantages of Glass Insulator: DisadvantagesofGlass Insulator: There are five types of insulators: Pin type insulator 2.
Suspension type insulator 3. Strain type insulator 4. Shackle type insulator 5. Stay type insulator 1. Pin type insulator: Pin Insulator is earliest developed overhead insulator, but still popularly used in power network up to 33 KV system.
Pin type insulator can be one part, two parts or three parts type, depending upon application voltage. In 11 KV system we generally use one part type insulator where whole pin insulator is one piece of properly shaped porcelain or glass. As the leakage path of insulator is through its surface, it is desirable to increase the vertical length of the insulator surface area for lengthening leakage path. Suspensiontype insulator: In higher voltage, beyond 33KV, it becomes uneconomical to use pin insulator because size, weight of the insulator become more.
Handling and replacing bigger size single unit insulator are quite difficult task. For overcoming these difficulties, suspension insulator was developed.
In suspension insulator numbers of insulators are connected in series to form a string and the line conductor is carried by the bottom most insulator. Each insulator of a suspension string is called disc insulator because of their disc like shape.
When suspension string is used to sustain extraordinary tensile load of conductor it is referred as string insulator. When there is a dead end or there is a sharp corner in transmission line, the line has to sustain a great tensile load of conductor or strain.
A strain insulator must have considerable mechanical strength as well as the necessary electrical insulating properties.
The shackle insulator or spool insulator is usually used in low voltage distribution network. It can be used both in horizontal and vertical position. The use of such insulator has decreased recently after increasing the using of underground cable for distribution purpose. The tapered hole of the spool insulator distributes the load more evenly and minimizes the possibility of breakage when heavily loaded.
The conductor in the groove of shackle insulator is fixed with the help of soft binding wire. For low voltage lines, the stays are to be insulated from ground at a height. The insulator used in the stay wire is called as the stay insulator and is usually of porcelain and is so designed that in case of breakage of the insulator the guy-wire will not fall to the ground. A circuit breaker is the equipment, which can open or close a circuit under normal as well as fault condition.
A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by over current or overload or short circuit.
Its basic function is to interrupt current flow after protective relays detect a fault. The Circuit Breaker mainly consist of fixed contacts and moving contacts. There is an arrangement stored potential energy in the operating mechanism of circuit breaker which is realized if switching signal is given to the breaker. The potential energy can be stored in the circuit breaker by different ways like by deforming metal spring, by compressed air or by hydraulic pressure.
According to different criteria there are different type of circuit breaker: According to their arc quenching media the circuit breaker can be divided as: A high-voltage circuit breaker in which the arc is drawn in oil to dissipate the heat and extinguish the arc; the intense heat of arc decomposes the oil, generating a gas whose high pressure produced a flow of fresh fluid through the arc that furnishes the necessary insulation to prevent a re-strike of the arc.
The arc is then extinguished, both because of its elongation upon parting of contacts and because of intensive cooling by the gases of oil vacuum. Fast operations, suitability for repeated operation, auto re-closure, unit type multi break constructions, simple assembly and modest maintenance are some of the main features of air blast circuit breakers.
The compressors plant necessary to maintain high air pressure in the air receiver. The air blast circuit breakers are especially suitable for railway and arc furnaces, where the breaker operates repeatedly. Air blast circuit breaker is used for interconnected lines where rapid operation is desired.
Air is taken from the compressed air system. Three hollow insulator columns are mounted on the reservoir with valves at their basis.
The double arc extinguished chambers are mounted on the top of the hollow insulator chambers. The current carrying parts connect the three arc extinction chamber to each other in series and the pole to the neighbouring equipment. Since there exist a very high voltage between the conductor and the air reservoir, the entire arc extinction chambers assembly is mounted on insulators.
In such circuit breaker, sulphur hexafluoride SF6 gas is used as the arc quenching medium. The SF6 is an electronegative gas and has a strong tendency to absorb free electrons. The SF6 circuit breakers have been found to a very effective for high power and high voltage service.
It consists of fixed and moving contacts. It has chamber, contains SF6 gas. When the contacts are opened, the mechanism permits a high pressure SF6 gas from reservoir to flow towards the arc interruption chamber.
The moving contact permits the SF6 gas to let through these holes. A typical SF6 circuit breaker consists of interrupter units. Each unit is capable of interrupting currents up to 60 KA and voltage in the range KV.
A number of units are connected in series according to system voltage. SF6 breakers are developed for voltages range from to KV and power of 10MVA rating and with interrupting time of 3 cycles and less.
SF6 circuit breaker The use of SF6 circuit breaker is mainly in the substations which are having high input kv input, say above kv and more. The spring type of circuit breakers is used for small kv stations. The spring here reduces the torque produced so that The spring type is used for step down side of kv to 33kv also in 33kv to 11kv and so on. They are only used in low distribution side.
Vacuum circuit breakers are the breakers which are used to protect medium and high voltage circuit from dangerous electrical situations. Like other types of circuit breakers, vacuum circuit breakers are literally break the circuit so that energy can not continue flowing through it, thereby preventing fires, power surge and other problems which may emerge. These devices have been utilized since the s and several companies have introduced refinements to make them even safer and more effective.
Isolator is used to ensure that an electrical circuit is completely de-energized for service or maintenance. An isolator is essentially a knife Switch and is design to often open a circuit under no load, in other words, isolator Switches are operate only when the line is which they are connected carry It is also capable of carrying current under normal circuit conditions and carrying for a specified time, current under abnormal conditions such as those of short circuit.
An isolator is a mechanical switch that is manually operated. Depending on the requirement of a given system, there are different types of isolators. With isolators, one is able to see any open circuit physically as compared to circuit breakers where no physical observation can be made.
Since no technique for arc quenching exists in isolators, the operation of electrical isolators should only be carried out when no possible current is flowing through a circuit. An isolator should not be used to open a completely closed live circuit. Additionally, live circuits should not be completed and closed using an isolator.
This is to avoid large amounts of arcing from taking place at the isolator contacts. Hence isolators should only be opened after a circuit breaker is open and should be closed before closing a circuit breaker. Electrical isolators can be operated using a motorized mechanism as well as by hand. Hand operation happens to be cheaper, compared to a motorized arrangement. As no arc quenching technique is provided in isolator it must be operated when there is no chance of current flowing through the circuit.
No live circuit should be closed or opened by isolator operation. A complete live closed circuit must not be opened by isolator operation and also a live circuit must not be closed and completed by isolator to avoid huge arcing in between That is why isolator must be open after circuit breaker is open and these must be closed before circuit breaker is closed.
Isolator can be operated by hand locally as well as by motorized mechanism from remote position. Motorized operation arrangement costs more compared to hand operation; hence decision must be taken before choosing an isolator for the system whether hand operated or motor operated economically optimum for the system.
For voltage up to KV system hand operated isolators are used whereas for higher voltage systems like KV or KV and above motorized isolator are used. Tandem isolator, often called split breaker or double breakers, provides two separate circuits in the space of rectangular sized breaker opening. Every circuit breaker panel has a limited number of circuits available. The problem is that when the openings are all used up and you still need to add another circuit, what do you do you?
You could change the electrical panel or double up circuits on a breaker, but this could place to much load on a particular circuit. So what then? The answer that many have found is tandem breaker. This type of breaker is the same size as any other breaker, but it has its difference. Tandem Isolator The relay room is separate from the control room.
The protection system is so fast that it can detect a fault within 30 ms and hence the circuit breaker can be operated within as less as 80 ms.Show More. This earthing rod system is not coupled to the main substation earthing grid.
The insulators are subjected to high voltage discharge up to 80 KV for 10 seconds followed by proper frequency voltage discharge up to 80KV for 5min. It is so designed that it attains its operating moment of force by interacting with the magnetic field of the voltage and current source it protects.
Firstly the inductive load is not connected 24X7, so the capacitor bank will not be utilized for its full potential. This pressure should be maintained during storage; if necessary by filling N2 Bushings - generally transported in wooden cases in horizontal position and should be stored in that position.
The State Transmission utility shall exercise supervision and control over the intra- State transmission system. The active power, the power required to run all the electrical appliances, is mainly used to run inductive loads. The Ceralin production for commercial use was started in A switching substation is a substation which does not contain transformers and operates only at a single voltage level.