Operation of impedance,reactance and admittance relay. Using event recordings to verify protective relay operations a. More specifically, the relay operates depending upon the impedance between the point of fault and the point where relay is installed. The calculation of the three basic transmission line parameters is presented in the following sections 17. Microcontroller based distance protection of transmission line.
Lesson 6 mho type and reactance type distance relay free download as word doc. It is the a representative diagram of impedance or reactance or admittance relay characteristics on rx plane with r in x axis and x in y. The selection of the mho relay was based on reasons previously. Introduction digital fault recorders dfr and modern microprocessorbased relays have records consisting of oscillographic waveforms and event logs that can give the necessary information needed to. Switchgear and protection notes sgp notes sgp pdf notes. Distance relay protection relay telecommunications.
In reactance relay the operating torque is obtained from the current and the restraining torque by the current and voltage of the directional element. Srikakulapu free download as powerpoint presentation. Power system fault analysis using fault reporting data of numerical relays dr. There are many types of distance relay characteristic such as mho, quadrilateral, reactance, admittance, polarizedmho, offset mho etc. Andrichak general electric company malvern, pa introduction the single line to ground fault is the most common typ eof fault that occurs on transmission lines, and ground distance functions are often used for the detection of these faults.
Pictorial glossary the pictorial glossary includes definitions and illustrations for many terms that are frequently used in the electrical industry. Larger reactance leads to smaller currents for the same voltage applied. Schematic diagram of the carrier current scheme is shown below. Desired maximum torque angle is obtain with the help of rc circuit. It is rather difficult to separate one reactance from the other. Transformer construction a transformer consists of two windings coupled through a magnetic medium. In this relay the operating torque is obtained by current while the restraining torque due to a current voltage directional relay. Terms that are underlined and italicized are included in the glossary as a separate definition. It embeds all the latest communication protocols on serial or ethernet links. The detailed can be saved in a separate file for future reference and use. Directional operation of relay is used where the selectivity can be achieved by.
This method is based on pattern recognition and classification. The current element developed positive torque and a currentvoltage developed directional element which opposes the current element depending on the phase angle between current and voltage. The input power which is measured in the short circuit test is unlikely to be the same as v i calculated from measurements. Resonance and tuning methods american radio relay league. For this reason, the two reactances are combined together and the sum. Pdf two questions about zerosequencereactance relay to overcome the disadvantages of high fault resistance for single phase to earth. Basics, maintenance, and diagnostics vii contents continued page 4.
Pdf study on reactance relays for single phase to earth fault on. The techniques, method and practices to provide this coordination are well established but scattered in various textbooks, papers and in relay manufacturers literature. The function will not operate dynamically because the angle a between v op and the initial polarizing signal voltage at r elay prior to the fault is much. Lesson 6 mho type and reactance type distance relay scribd. Ground distance relays understanding the various methods of residual compensation, setting the resistive reach of polygon characteristics, and ways of modeling and testing the relay 2 residual compensation and zerosequence current compensation most ground distance relays are designed so that they measure and can be set in terms of positive. There are many types of distance relay characteristic such as mho, reactance, admittance, quadrilateral polarizedmho, offset mho etc. Rated values rxzk 21h rated voltage ur 100 v rated current ir 1 a or 5 a scale constant is 0,1 0,2 0,4 and 1,0 x i r setting ranges. The two windings of the transformer are called high voltage winding and low voltage winding. Protection accessories, such as a gasandoilactuated relay and pressure relief device, iiec be mounted on the transformer during the test.
Construction and disadvantages of reactance relay, electrical. Using event recordings to verify protective relay operations. Power system protection and switchgear by badari ram, d. These relays are known as distance relay or impedance relay. The directional component is masterminded to create greatest negative torque when its present slack behinds its voltage by 90. Numerical relays are based on the use of microprocessors. As a proven useful tool for prototyping, the labview graphical development platform delivers a numerous solutions to a wide variety of applications such as instrumentation control, embedded monitoring and control systems, data acquiring and processing, automation test and validation systems, etc. There is one type of relay which functions depending upon the distance of fault in the line.
The actuating impedance in the relay is the function of. Discuss with necessary circuit diagram, the principle of operation of an induction disc relay. This paper presents a new approach, known as artificial neural network ann to overcome the effect of fault resistance on relay maloperation. Impedance relay and protection rxzk 21h, 22h, assemblies.
Implementation and evaluation a simulink model of a. The im pedance of a capacitor or an inductor changes as the frequency of operation changes. Xf, xf1 and xf2 are forward reactance reach settings. Implementation and evaluation a simulink model of a distance. This calculator provides a good estimate based on industry standard calculation methods and cable manufacturing data. A big difference between conventional electromechanical and static relays is how the relays are wired. Distance relay protection free download as powerpoint presentation. Both the magnetization reactance and the leakage reactance are present at the same time. Although this decay is quick, the dccurrent component could last enough timeto be detected by the protective relay equipment, particularly when fast fault clearing is very needed to maintain system stability or prevent the damaging. The directional element is so designed to give maximum torque angle mtarca of 90 degree.
The part of the impedance that is frequency dependent is called capacitive reactance in capacitors and inductive reactance in inductors. Setting procedures are only discussed in a general nature in the material to follow. Every type of characteristics has different intended function and theories behind. Ee6702 protection and switchgear notes r20 5,566 views. Types gcx51a, gcx51b directional distance reactance relay category.
Application is made for permission to interconnect to the xcel energy electric distribution system as follows. Relay classification, principle of different types of electromagnetic relay. Only one of the three phases is shown, and several auxiliary relays are omitted. Switchgear and protective devices 310 modulei 10 hours protective devices. The rate of decay is related to the system reactance and total resistance. Protection and switchgear miet engineering college. The following calculator computes the resistance, inductance, inductive reactance, capacitance, charging current, and surge impedance for medium voltage shielded power cables. International standard iec 600765 note 1 at the end of the tests, if the windings are provided with tapping, the reactance must be measured for all the tapping positions at which the shortcircuit tests. Introduction to labview and basic labview based electrical projects. Distance relay or impedance relay working principle types. Impedance relay and protection assemblies rxzk 21h, 22h, 23h and razk 1mrk 509 006ben page 3 technical data table 1. Reactance relay is an overcurrent relay with directional constraint. In protectiverelaying terminology, however, an impedance relay has a characteristic that is different from that of a relay responding to any component of impedance. This is the time between the instant of closing of relay contacts to the instant of final arc extinction inside the medium and removal of the fault.
Based on more than 100 years of experience in network protection relays, easergy p3 benefits from the reliability of. Let us suppose for the moment that the impedance at the primary terminals is a series combination of resistance r % and reactance x %. With a neat schematic diagram, explain the protection of transformer with differential protection. Transformer protection application guide this guide focuses primarily on application of protective relays for the protection of power transformers, with an emphasis on the most prevalent protection schemes and transformers. I want to find out the resistance and the reactance of an motor coil. The induction cup or twofold induction loop structures are most appropriate for impelling reactance type distance relays. In this simulation, mho type distance relay was used as the distance protection scheme. Philosophy of protection, nature, causes and consequences of faults, zone of protection, requirements of a protective scheme, basic terminology components of protection scheme. This is the time between the instant of occurrence of the fault to the instant at which the relay contacts open. Relaytorelay and relaytocomputer communication paths for a digital relay are shown in the following figure. I can measure the magnitude of the current through the coil using a dmm.
Easergy p3 is a complete range of protection relays for medium voltage applications, including feeder, motor, transformer, and generator protection. Introduction the need to coordinate generator protection with generator control and load capability has been well known to generator protection engineers. Operating principles of relays the universal relay torque equation rx diagram. Pdf remote fault estimation and thevenin impedance. A relay that operates on the quantities given in figure 1, can be easily analyzed for the conditions of figure 5 by using phasors as shown in figure 6.
This relay consists of two units an overcurrent element and a currentvoltage directional element. Switchgear and protection by sunil s rao, khanna publishers. Derive the torque equation for electromagnetic relays when used for a. Power system fault analysis using fault reporting data of. In electric and electronic systems, reactance is the opposition of a circuit element to the flow of current due to that elements inductance or capacitance. This implies that reactance relay is an overcurrent relay with directional restraint. For example, if the voltage across the coil is 230v ac and the current through the coil is 10a, impedance, z 23010 23 ohm. Operating characteristic of an impedance relay on an rx diagram. For calculations you can choose which formula to use for inductive reactance, either 2l or. So use of a pattern recognizer can improve the relay performance.
When used to make bidirectional measurements on a 2port device, the calibration process requires ten separate steps, five in the forward direction fwd and five in reverse rev. Discuss the fundamental requirements of protective relaying. The scheme utilizes the magn itudes of resistance and reactance as inputs. Short, fwd and rev open, fwd and rev load, fwd and rev. Reactance relay is normally preferred for protection. Reactance relay operating torque is obtain by current and restraining torque due to a current voltage directional relay structureinduction cup type operating torque interaction of fluxes produced by 1,2 and 3 proportional to square of the current. Power system analysis unit i the power system an overview and modelling structure of electric power system current scenario complex power concepts of real and reactive power per phase analysis modeling of generator, transformer with offnominal tap ratio, transmission line per unit. Low reactance earthing 9 compensation reactance earthing 10 solidly earthed neutral 11 shortcircuit currents introduction to shortcircuits 12 types of shortcircuit 14 shortcircuit across generator terminals 16 calculation of shortcircuit currents 17 equipment behaviour during shortcircuits 18 sensors phasecurrent sensors ct 19. Fundamentals of power system protection by paithankar and s. L, but 2l is more commonly used, one reason being that scientific. The reactance relay is designed to measure only reactive component of the line reactance. Numerical relays protection and control products for. This implies updating of the relay settings, which represent a change in the power.
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