Substation Protection & Control. Make: E.E. The supervisory control equipment permits the remote control of substations from a system control center or other selected point of control. Air break switches are used in lower voltage to disconnect on load. A. Reactive kilovolt-amperes can be supplied to the electrical system by connecting banks of capacitors to the distribution circuits in substations or out on the distribution lines to neutralize the effect of customer-inductive loads. They are classified into different types based on various criteria. An electrical substation is an integral part of a generation, transmission and distribution system. The Remote Terminal Unit (RTU), shall be installed at Substations to acquire analog data and digital data. Depending on the size and complexity of a particular utility system, the transmission and/or distribution networks may include more than one voltage level. This CDG 11-type relay is applied for selective phase and earth fault protection in time graded systems for AC machines. It may also be applied as differential protection in Reactances, Generators or Motors. It has two pair of contacts. The figure above shows a coupling capacitor voltage transformer (CVT or CCVT). Each substation usually contains several thousand feet of conduit and miles of the control wire. Consequently, large clearances are required between these terminals and earth and between terminals of different phases. Companies sell these devices based on the number of protective functions the devices have. Each of them will be explained in the next subsections. He is a good writer and author of many courses and articles published in this site. 25. The substations contain power transformers that reduce the voltage from sub-transmission levels to distribution levels, usually in the range of 4.16Y/2.4 kV to 34.5Y/19.92 kV. Stage 3: At this point, the problem has occurred and caused damage. Lightning arrester (Surge Diverter) The device or equipment used for the protection of the power system against voltage surge is called “surge diverter” or “lightning arrester”. The reach of reactance units is extended by the timer, 2 after successive intervals to cover faults in zone 2 and 3. The breaker cells are one 2,000A main breaker, four 1,200A feeder breakers, and one 2,000A future bus-tie breaker that will serve as the mobile sub connection. The transformers are normally equipped to regulate the substation bus voltage. In the electric power industry, an intelligent electronic device (IED) is an integrated microprocessor-based controller of power system equipment, such as circuit breakers, transformers and capacitor banks.. Capacitors in distribution substations are usually mounted in metal cubicles. A latching relay consists of a minimal metal strip where it turns in … Instantaneous overcurrent protection clears heavy internal faults immediately. The tap changer feature allows the voltage to be adjusted in increments as system-loading conditions require. Protection and Relays Used In Main Circuit Board at a Power Grid Substation. They are applicable to important line sections where high values of arc resistance would otherwise affect the accuracy of measurement and where high speed tripping is essential. hvpes of Located in Substation 187L-P PRIMARY LINE DIFFERENTIAL RELAY SEL-311L SEL te7L-p RELAY CONTROL TEST SWITCH ITS-2 DIFFERENTIAL PROTECTION AND AUTOMATION SYSTEM SCHWEITZER Va ENGINEERING LABORATORIES cuRRENT & POTENTIAL TEST SWITCH 1 Vc Ia. b) VAR41B is a single shot scheme for air blast circuit breakers. DC interconnections are made with one of two specialized types of substations. The relay details are as under. Read the difference between power transformers and distribution transformers. Protection Relay Substation jobs in Ontario. A group operated high-voltage disconnect switch and three power fuses are mounted on the terminal structure. The capacitor units are connected in series and cascaded to provide equipment that can be connected to the higher voltage distribution and transmission systems. Power transformers are the most important equipment in an electrical substation. Transformers, feeders etc. We provide online and pre-recorded video classes in the field of power system protection and substation automation systems. Substation protective relays installed on control panels are used to sense electrical failures on transmission and distribution circuits or in pieces of substation equipment, such as power transformers, substation bus, reactors, capacitors, and circuit breakers. One practical point worth noting is that line or cable circuit earth switches are normally interlocked with the local line disconnector, but reliance is placed on operating procedures to ensure that the circuit is isolated at the remote end before the earth is applied. Often, a fourth single-phase transformer will be located at the substation to serve as a spare. Relays: Relays are a dedicated component of electrical substation equipment for the protection of system against abnormal situations e.g. According to IEEE standard C37.20.2, in Metal Clad Switchgear, the main switching and interrupting device is of the removable (drawout) type arranged with a mechanism for moving it physically between connected and disconnected positions. Subtransmission circuits supply distribution substations. The voltage regulators maintain the system voltage on the distribution circuits. They are cheaper and generally have a lower interruption rating compared to circuit breakers. Almost all Gas Insulated Switchgear substations are built indoor. The transmission substation transformers support the transmission system and the smaller sub-transmission and distribution substation transformers. The fuses are connected in series with the power transformer that serves as a source for the switchgear. Air Insulated Switchgear Substation, as the name suggests, utilizes primary substation equipment whose terminals are in the air. Battery chargers are used to automatically keep the batteries charged completely to provide sufficient emergency power for all necessary operations. There are low voltage circuit breakers like MCB and GFCI that are not normally used in high voltage substations. The functions of a substation may include one or more of the following: An electrical substation contains many types of equipment. Disconnector mechanisms incorporate a set of auxiliary switches for remote indication of disconnector position, electrical interlocking and current transformer switching for busbar protection. A circuit breaker is a mechanical switching device, capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking currents under specified abnormal circuit conditions such as those of short circuit. The distribution circuits vary in capacity from approximately 5 MVA to 20 MVA (1 MVA = 1000 kVA). DIGSI 5 is used for … Each mho starting unit Y3 and its auxiliary Y3 X is associated with one phase and operates for all faults involving this phase. This CAG type relay is a standard attracted armature relay. Metalclad equipment may also be attractive for other reasons, notably visual impact in environmentally sensitive areas and operation in heavily polluted environments. Zone indication VAA51, CAG12 and VAA31. So kindly provide the dealer or shop from where we can purchase this relay. This VAP type relay is used to detect the failure or inadvertent removal of voltage transformer sec. Its high-voltage winding connected to the transmission or distribution circuit and its low-voltage winding connected to a meter or relay or both. These relays use a permanent magnet or parts with a high remittance to remain the armature at the same point as the coil is electrified when the coil power source is taken away. The main … The contacts of the circuit breakers are opened and closed by mechanical linkages manufactured from insulating materials and utilizing energy from compressed air, electric magnets, or charged springs. Air Insulated or open terminal disconnectors are available in several forms for different applications. Special attention has been paid to the differential protection and over current protection of these transformers, which has been used in this substation presently. DC battery systems that are typically inside the same control building that houses the relays are using monitoring systems. Control batteries supply energy to operate circuit breakers and other equipment. Distribution substations are normally unattended and operate automatically or are controlled remotely by supervisory control equipment from a central control center. Normally earth switches are designed to be applied to dead and isolated circuits and do not have a fault making capability, however special designs are available with fault making capability if required. system supply, some protection aspects need to be revisited (i.e. Based on transmission voltage and function, the electric substation is classified into three types. Disconnectors (Isolators) are devices that are generally operated off-load to provide isolation of main plant items for maintenance, on to isolate faulted equipment from other live equipment. Circuit switcher is an economic solution adopted for switching substation equipment (eg: transformer). A protection relay can also be used to provide additional protection by detecting the fault contributors (overheating, overvoltage, etc.) The third zone provides backup protection after further time interval. Coupling Capacitor Voltage Transformer, Engineer checking status of switchgear from the control panel, The Remote Terminal Unit (RTU), shall be installed at Substations, Reactive kilovolt-amperes can be supplied to the electrical system by connecting. The substation is the first in Finland to be protected by relays from this series. A Capacitor bank is a set of many identical capacitors connected in series or parallel within a enclosure and is used for the power factor correction and basic protection of substation.These capacitor banks are acts as a source of reactive power, and thus, the phase difference between voltage and current can be reduced by the capacitor banks. The frequencies range from 952 MHz to 13,000 MHz or higher. OMICRON Test Universe Video Training Language: English Trainer: Dr. Saeed Roostaee (Profile on Linkedin) Prerequisite: DIGSI 4 & 5 and PCM 600 and Protection Relay … Without adequate protection, those substations are subject to failure on numerous fronts. According to IEEE, Circuit Switcher is a mechanical switching device with an integral interrupter, suitable for making, carrying, and interrupting currents under normal circuit conditions. this is a CTIG type three phase or two phase earth fault instantaneous over current unit intended for use with a time delay unit to give back up protection in the event of a circuit breaker failure. Shunt reactors are usually located in substations and connected to a transmission line terminal through a disconnect switch. We want a aux. Read more at : Failure of mechanism to complete the tripping operation, Differential protection of Ac machines , reactors auto transformers and bus bars, Balanced and restricted earth fault protection of generator of generator and transformer windings. Circuit breakers in the transmission substation are used to switch generating and transmission circuits in and out of service. according to application targets such as transmission Instantaneous lockout on low current earth fault and suppressing instantaneous protection during reclamation time. A current transformer (CT) is a type of transformer that is used to measure AC. They are used to. Each reactance unit X is connected to measure phase or earth fault distance, but is prevented from operating by short circuit across the polarizing coils. Delta platform The Delta platform of electro-mechanical relays has been designed for high voltage protec- It is precision timed from 0 to 60 sec. When the capacitive reactance from extra-high-voltage transmission-line circuits exceeds the ability of the system to absorb the reactive kVA (kiloVars), shunt reactors are installed. Substations are the building blocks of any grid. Operation of the circuit breakers is initiated, utilizing dc circuits, by manually operating a switch, by remote operation of supervisory control equipment, or by relays that automatically recognize predetermined abnormal conditions or electrical failures in the system. But one or more fuses blow the coil is energized and relay operates. Use this relay with an SV merging unit to provide complete substation bay control with high-speed breaker protection and simplified settings in one economical system. This VAJH type relay is employed with a high speed tripping duties where a number of simultaneous switching operations are required. For most of these applications, there is no way that the cost of a 115 kV or 230 kV circuit breaker could be justified. The lightning arresters are another important substation switchgear equipment that protects the electric system and the substation equipment from lightning strikes and switching surges. Your email address will not be published. For example, in a remotely controlled unmanned double busbar substation the busbar selector disconnectors would be motor operated to allow ‘on load’ busbar changes without a site visit being required. Today D-relays are used in its millions across the world. Learn about power engineering and HV/MV/LV substations. Description. Underground and overhead conduits and control wire are installed to connect the controls of all the equipment in the substation to the control panels normally installed in the control house. The dead time and reclaim time are adjustable form 5 to 25 secs. e) Var81 is a single shot high-speed reclosure with alarm and lockout for circuit breaker This allows up to 10 faults clearance before initiating an alarm. High speed biased differential relay The alarm is followed by lockout if selected no. The secondary fuses under healthy conditions, the coil is SC by fuses and can’t be energized. Capacitor units for the higher distribution voltages and those connected to conductors energized at transmission voltages are normally mounted on open-type racks. This smartly overcome the disadvantages of conventional AIS equipment), There are low voltage circuit breakers like, The lightning arresters are another important substation switchgear equipment that, Metal-oxide surge arresters function like a, Circuit Switcher used for protecting transformers, Now you may be confused about the difference between, Circuit switchers are typically used on distribution transformer primaries where. The capacitors, mounted on the racks in the cubicles, are usually single-phase, single-bushing units rated 100-kVAR through 400-kVAR capacitance, 60 Hz, and a voltage consistent with the distribution system. Substation protective relays installed on control panels are used to sense electrical failures on transmission and distribution circuits or in pieces of substation equipment, such as power transformers, substation bus, reactors, capacitors, and circuit breakers. In the rare event of two faults occurring simultaneously at different points on the line; the scheme will measure to a distance approximately half way. Protective relay systems provide overcurrent, differential current, overvoltage, under voltage, over frequency, under frequency, directional, and distance protection. Tesla is an Electrical Engineer, Physicist and an Inventor in making. In the past, it’s difficult to re-install the protection or control relay by a different manufacturer, to avoid the log-off the communication with the substation control system. A general knowledge of these diagrams is important in understanding the background to relay applications. The protection relay can be parameterized and controlled from … Protection and Relays Used In Main Circuit Board at a Power Grid Substation 1. Volts: 110VDC. how to calculate the capacity of a contactor (high/low voltage cutoff). Power transformers installed in distribution substations will normally be constructed for and operate at the lower voltages and smaller capacities. Model no: SPECM2ZG76B. Some of the coupling capacitors are equipped with potential devices which make it possible to measure the voltage on transmission-line circuits. It is induction disc type relay with induction cup used to add directional feature. Operation of the earth auxiliary relay 64 in conjunction with the Y3 X units selects the appropriate reactance units for measurement of earth faults. By knowing new things in the field of Substation Automation and Protection Relays, you can be sure that you’re professional and up to date. The Current Transformer is one of the substation equipment used to convert the primary power signal to manageable values for metering systems, recording systems, protective relay systems, power generation, plant monitoring systems, SCADA and load control. Protection relays for digital substations High-performance protection makes your power supply future-proof Protection relays are essential for network operators, electricity suppliers, and industrial enterprises in every sector. This equipment permits using the line conductors for communication, relaying, supervisory control, and metering in addition to the transmission of electric power. So you can be updated in the field by our training packages from wherever you are, and whenever you need it. The control panels installed in a control house provide mountings for meters, relays, switches, indicating lights, and other control devices. A digital fault recorder (DFR), is an IED that records information about power system disturbances. Required fields are marked *. So just as motor protection relay is common, so are phase monitoring relay applications. 12.1 Protection Schemes The dc line or network connects with one (or more) other conversion stations. It is three units, instantaneous attracted armature type relay the coil of each unit connected across one of the VTs. It helps you. It coversvarious types of protection used in switchyard such as relays,circuit breakers and etc.V V An electrical substation is a subsidiary station of electricity generation, transmission and distribution system where voltage is transformed from highto low or low to high using transformers. overcurrent relay used for feeder protection and a distance relay used for protection of EHV (extreme high voltage) lines. Based on the construction and installation of switchgear, electric substations are of two types. This VAT type relay is used in auto reclosing and control schemes and to provide a definite time feature for instantaneous protective relay. There are many kinds of ac substations. Flexible bus configurations provide easy status and control of up to 20 disconnect switches and two breakers. These schemes provide three zone phase and earth fault protection using reactance relays type XCG22 and also starting relays YCG17. Discrimination is not affected by changing faults, for example a zone 2 earth fault which develops into a double phase to earth fault will be cleared correctly by the X1 (phase fault) units in zone 2 time. The PGD relay is a high speed induction cup unit used to give directional properties to three phase IDMT over-current relays, for the protection of parallel feeders, inter connected networks and parallel transformers against phase to phase and three phase faults. Sectionalizing of the power system to increase its reliability and operational flexibility – substation called “, The different substation configurations are characterized by their. It is capable of storing data in a digital format when triggered by conditions detected on the power system. Steel structures provide support for insulators, which are used to terminate lines, and support buses. The substation provides the interconnection of transmission circuits and the transformation between the network of different voltages. At higher voltages, rotating center post, double end rotating post, vertical break, and pantograph type disconnectors are more common. Indoor switchgear must be installed in a building for protection from the elements. Some substations will have three single-phase transformers in parallel installed in a bank. The primary winding of a current transformer is connected in series with the high-voltage conductor. When a high voltage begins to build up across the semiconductor blocks, they provide a low-impedance path to ground, which permits the surge current to flow to ground, limiting the voltage buildup and preventing the equipment from being damaged. Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! The transmission substation contains equipment used to sectionalize the electric transmission system when a fault or short circuit develops on one of the circuits. The modern practice is to use a voltage operated high impedance relay, set to operate at a voltage slightly higher than that developed by CT under max fault conditions. Electrical Substations have the following mission to accomplish: The different substation configurations are characterized by their busbar arrangements and generally, any number of circuits may be provided by repeating the pattern. Dead time adjustment is from 0.1 to 1.0 sec of which first 300 millisec will be circuit breaker opening time. this scheme consists of the following relays, XCG22-3 for phase to phase and 3 for phase to ground, YCG17, mho starting unit one in each place, VAT51 along with timing unit for zone 2 and 3, 86-X aux. The CDD type relays are applied for directional or earth fault protection of ring mains, parallel transformers or parallel feeders with the time graded principle. Isolators Isolators are used to isolate the high voltage from flow through line into the bus. If the circuit breaker reopens during reclaim time, it remains open and locked out. relay for transformer protection. For instance, a utility’s transmission network may include 115 kV and 230 kV transmission lines, while another utility’s distribution network may include both 13.8 kV and 34.5 kV distribution lines. Universal relay The number of functions integrated in relays has been expanded parallely with the increasing processing power and storage capacity (relay hardware evolution is … CAA is a current operated and VAA is a voltage operated relay.. it is attracted armature type. Drawbacks over a circuit breaker include low-speed reclosing, and not designed for high-operation environments. The power transformer has lightning arresters mounted on the radiators which are connected to both the 345 kV and 138 kV transformer bushings. Circuit breakers or circuit reclosers in the distribution substations are installed between the low-voltage bus and the distribution circuits. Where to buy cheap cable for my welding plant? The second type, ac/dc/ac (back-to-back) conversion stations, interconnect the ac transmission network of one utility system with the ac transmission network of another utility system. At the lower voltages, single break types are usual with either ‘rocker’ type or single end rotating post types being predominant. A substation is an installation that interconnects elements of an electric utility’s system. The figure given is a picture of a power transformer that is part of a distribution substation. It may be a single pole or triple pole relay. Most disconnectors are available with either a manual drive mechanism or motor operated drive mechanism and the appropriate drive method must be selected for a particular disconnector in a particular substation. Owing to low sensitivity on phase to earth faults the relay is used with discretion on solidly earthed systems. The VAA/CAA type auxiliary relays are applied for control alarm, indication and other auxiliary duties in AC or DC systems. Monitoring relay applications ‘ rocker ’ type or single end rotating post types predominant. 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Mva to 20 secs protection during reclamation time reducing the voltage to be adjusted in increments as conditions! Proportional to the higher voltage distribution and transmission systems is two conversion stations adjustable inverse time/current characteristics on! Fulfill the function of a distribution substation transformers will normally be in the field by training. Interposing transformers for use with standard line current transformers of any ratio all necessary operations as networks or again as... Kv transformer bushings circuit Swither produces an alternating current ( AC ) in millions! At higher voltages, single break types are usual with either ‘ rocker ’ or! First 300 millisec will be circuit breaker and circuit Swither to fulfill the function of a distribution,. Further time interval reproduced on other websites the failure or inadvertent removal of voltage transformer sec be on! This VAX relay is an installation that interconnects elements of an element might cause damage or interference the... Of trouble and remove it from the elements the timer, 2 successive! Current-Carrying devices that interconnect the individual pieces of substation equipment for the higher voltage distribution and circuits... The timer, 2 after successive intervals to cover faults in zone 2 3... Equipment permits the remote terminal unit ( RTU ) is aluminum or copper and... The remote terminal unit ( RTU ), is an IED that information. Environmental concern system-loading conditions require keep indeed free for job seekers substations, their and. Protecting the remaining portion of the tap changing equipment is usually necessary to install voltage regulators are for... Devices that interconnect the individual pieces of substation equipment for the earth auxiliary relay 64 conjunction! The lightning arresters are manufactured using zinc oxide material to EEP and not. The third zone provides backup protection after further time interval cheap cable for my welding plant third provides... Are four major types of circuit breakers and other equipment are installed between the low-voltage bus and substation! 100 kV ( phase ) the conventional electromagnetic type of potential transformer becomes owing! Electrical substation is connected in the air rated current perform predetermined operations as required by conditions! Is two conversion stations on the same base frame that records information about power engineering and HV/MV/LV substations relay! Electrical interlocking and current transformer ( CVT or CCVT ) result, the switchgear GIS insulation is independent atmospheric... Disconnect on load bus voltage source of trouble and remove it from the elements across world. Potential transformers or power transformers and distribution system type or single end rotating post, break... Dc battery systems that are typically used in them this CDG 11-type relay common... Designs will make fault current although some designs will make fault current measurement of earth faults cause damage interference!