The pick-up of the relay is obtained by movement of the movable element in the relay. The actual source of the trip point of the relay must be located and replaced, if found defective. Thus the signalling and indicating systems must also be designed on a static basis. Relay pick up current Primary side = 0.7875 * 800 = 630A The amplified output is given to the output circuit to cause trip/alarm. Timing Circuit. A single coil which permits use …, COPYRIGHT © 2014 TO 2020 EEEGUIDE.COM ALL RIGHTS RESERVED, Introduction Control Techniques in Electric Drives, Introduction to Microprocessors and Control of…, Introduction to Economics of Power Generation, Directional Overcurrent Relays in Power Systems, Power System Protection Important Questions, Sequence Impedances of Transmission Lines, Condition for Reciprocity of a Two Port Network, Inductance of Single Phase Two Wire System, Input Output Interfacing 8085 Microprocessor, Impedance and Phase Angle of Series Resonant Circuit, Condition for Symmetry in Two Port Network, Half Subtractor and Full Subtractor Circuit. The trip circuit operates the circuit breaker which isolates the faulty section. The function will not oper-ate for an inductive fault behind them. The b) Surge divertors d) Over head lines Actual tripping of a static relay is obtained by. Where, Z is the fault impedance and is equal to ratio of V and I, Z R is the replica impedance in the relay, ɸ is the phase angle between V and I and θ is the relay characteristic angle. Relay Pickup current (Primary) = Plug Position (PSM) * Rated CT Primary current. Definition of Protective Relay. View Answer / Hide Answer c) UJT The burden or current transformers gets considerably reduced thus smaller CT.s can be used. b) After the distributor This obtained by converting 230V a.c. to 24V d.c. and in some cases station battery voltage of 110V to 24V d.c. Comprator:It compares the actual quantity with the pre-set quantity. When a differential current exceeding the setting of the relay flows, timer T1 is reset and timer T2 ⦠What does the first part consist of? c) None of these Ans: (d), a) SCR Which of the following statement is true? Economics of Operation page-1, Objective Type Question or MCQ of Power System Protection page-8, Objective Type Question or MCQ of Power System Protection page-7, Objective Type Question or MCQ of Power System Protection page-6, Objective Type Question or MCQ of Power System Protection page-5, Objective Type Question or MCQ of Power System Protection page-4, Objective Type Question or MCQ of Power System Protection page-3, Objective Type Question or MCQ of Power System Protection page-2, Objective Type Question or MCQ of Power System Protection page-1, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-11, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-10, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-9, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-8, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-7, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-6, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-5, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-4, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-3, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-2, Multiple Choice Question (MCQ) of Alternator and Synchronous Motors page-1. c) Independent of zone This relay can be used to isolate faults in transmission lines based on the conversion of 3-phase currents from analog to digital values and instantaneously issuing a trip signal if the actual line current is greater than preset value. Tripping of the bus is obtained when both the SR and dR operate simulta- neously. It is an electromechanical switch whose input is electrical with mechanical output.It is used to disconnect the faulty part of the circuit from the faulty part such that the due to the faulty part the whole circuit is not affected.It is achieved by comparing two quantities either in amplitude or in phase . b. c) The saturation voltage VCE for silicon transistor is same as that for germanium. d) Alloys, Multiple Choice Question (MCQ) of Electronics page-14:196. Ans: (b), a) After the transformer The materials whose electrical conductivity is usually less than 1 × 106 mho/m are c) Free electrons are always present in the semiconductor. Instantaneous relay is. In an actual relay, I threshold can be adjusted. Z Z R cos (ɸ â θ) ⥠0. d) None of these https://emadrlc.blogspot.com/2014/04/power-system-protection-course.html a) The saturation voltage VCF of silicon transistor is more than germanium transistor. b) Non-linear characteristic Introduction to Static Relays: Characteristic Functions of Protection Relay: Characteristic Functions of Protection Relay elements using different operating principles. d. All of these. The static relay only gives the response to the electrical signal. 1Also called the rated trip current or the ultimate trip current. Medium voltage switchgears are used for switching medium voltage loads through associated control, measuring, protective and regulating equipment. The stability setting applies only during external faults. d) Inner and bound electrons are always present in the semiconductor. Economics of Operation page-3, Objective Type Question or MCQ of B. AC - DC Conversion. Ans: (b), a) In three zones c) Before the transformer The mho function uses the current and voltage measured at the relay to determine if the ... than would be obtained with a self-polarized mho function. b) Resistance grounding Ans: (d), a) Straight line characteristic d) All of these b) CUJT c) 90 kms After operation of the measuring unit, the output is amplified by the amplifier. 3. Multiple Choice Question (MCQ) of Electronics page-15:211. Compared to the Electromechanical Relay, the Solid Static relay has longer life-span, decreased noise when operates and faster respond speed. This technical co⦠Static relays …, Generator Transformer Protection : Generator Transformer Protection â Protective relays, being component parts of electrical switchgear, should be closely associated with the control section of such systems, e.g. c) Transformer b) The saturation voltage VCE for germanium transistor is more than silicon transistor. d) Surge attenuators A simpliï¬ed block diagram of a single input static relay is given in the above figure. b) Conductors short circuit levels at the line ends, pre-fault conditions, i.e. Economics of Operation page-6, Objective Type Question or MCQ of B. Characteristic Functions of Protection Relay : Characteristic Functions of Protection Relay elements using different operating principles. d) None of these In a static relay the measurement is carried out by static circuits consisting of comparators, level detectors, filter etc while in a conventional electro-magnetic relay it is done by comparing operating torque (or force) with restraining torque (or force). Case-2 for New CT: New CT Ratio- 800/5A. Time vs. PSM Curve of Relay d) None of these Comparator. As the time setting multiplier is 0.1 here, actually the moving parts of the relay have to travel only 0.1 × 100% or 10% of the total travel distance, to close the relay contacts. If fault occurs at point A on load at bus 646, primary relay R 1 will operate first. A mho relay using the induction cup structure is shown in the figure below. The moving parts are absent. Single phase to ground fault Current Sampling From CTs. Electronic Relay. b) Bound electrons are always present in the semiconductor. (For a B19.5 thermal unit, 100% corresponds to 19.5.) The trip characteristics of the relay is obtained by keeping the system operating conditions constant, while the fault location (0â95% of the length of transmission Line 1) and fault resistance R f (from 0 to 200 Ω) are varied . Which of the following statement is correct? Reversal of current through the relay from I F1 to I F2 when C opens could then result in incorrect tripping of the healthy line if the directional unit R D operates before the impedance unit resets. b) Polarized type Primary winding of a current CT which is connected in series with the line to be protected. â Percent of thermal unit number, element number, or relay ratingis obtained by dividing the overload current by the number stamped on the thermal unit nameplate and multiplying by 100. Relay is a switch which senses fault in a system and once fault is sensed by the Relay, it issues trip command to the Circuit Breaker, CB to isolate the faulty section of the network from the healthy section. Ans: (d), a) Hinged armature type 25. Ans: (d), a) Persistent arcing grounds are eliminated Ans: (a). Multiple Choice Question (MCQ) of Electronics page-16:226. The various advantages of static relays are: 1. In an impedance relay, fault current is maximum if fault occurs near the, a) Relay 10% of 3 sec. d) All of these c) Insulators Introduction of Static relay The relay which does not contain any moving parts is known as the static relay. The results are all formulated and then evaluated in order to produce a conclusion and bring forward recommendations to Eskom in order to effectively ensure the Dedisa/Grassridge power system is reliable once b) 50 Kms These contacts in turns close and complete the circuit breaker trip coil circuit hence make the circuit breaker tripped for disconnecting the faulty portion of the electrical circuit from rest of the healthy circuit. : 4 The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, overvoltage, reverse power flow, over-frequency, and under-frequency. b) In two zones c) Transformers The plug …, Influence of Static Protective Relays : Influence of Static Protective Relays on the associated equipment like current transformers, voltage transformers, etc, Current Transformers Burdens on current transformers have a great influence on their design and for a long time the problems of …, Level Detector : Schmitt trigger or level detector circuits are very often employed in static relay circuits as a final stage before the trip coil circuit of the circuit breaker. - from the table α = 0.02, K = 0.14 - pick-up current setting = 1000 A x 0.8 = 800 A c) Balanced beam type Static Relay: The term âstatic relayâ is generally referred to a relay incorporating solid state components like transistors, diodes, resistors, capacitors, etc.In this type of relay, the functions of comparison and measurement are performed by static circuits wherein there are no moving parts. a) Semiconductors All versions are available with an S-value of : 0.5, 0.66, 0.80 and 0.85. These principles and design criteria determine how well the basic function is performed and how in practice it deviates from the ideal. Economics of Operation page-2, Objective Type Question or MCQ of B. The Relay detects the abnormal condition by continuously monitoring electrical quantities which are different The output device is activated and gives the tripping command to the trip circuit. Secondary of the CT and the operating coil. c) Surge absorbers In this type of relay, the functions of comparison and measurement are performed by static circuits wherein …, Time Delay Circuit : Time Delay Circuit â Several choices are available in the selection of suitable circuits for obtaining time delay depending on the magnitude of the time delay required. The output device activates the trip coil only when the relay operates. In such type of relays, the output is obtained by the static components like magnetic and electronic circuit etc. a) UJT A variety of control and interlocking schemes are used to achieve the above stated objectives. b) Under ground cables correlates to the actual tripping of a Static VAr Compensator (SVC). a) SCR b) Thyristors c) UJT d) None of these Ans: (d) 34. Micro controller based over voltage static Relay. This operation also involves considerable manual intervention which therefore necessitates the fulfilment of safety requirements laid down in International Standards. In individual relays, there is a wide variation. b) Minority carriers Lower part: The lower part of the Buchholz relay is concerned with the detection of serious or major faults and thus completes the trip circuit to open the circuit breaker operating the transformer. a. e) Holes and electrons simultaneously, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-20, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-19, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-18, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-17, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-16, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-15, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-14, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-13, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-12, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-11, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-10, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-9, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-8, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-7, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-6, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-5, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-4, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-3, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-2, Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-1, Objective questions and answers or MCQ of Electrical Machines page-22, Objective questions and answers or MCQ of Electrical Machines page-21, Objective questions and answers or MCQ of Electrical Machines page-20, Objective questions and answers or MCQ of Electrical Machines page-19, Objective questions and answers or MCQ of Electrical Machines page-18, Objective questions and answers or MCQ of Electrical Machines page-17, Objective questions and answers or MCQ of Electrical Machines page-16, Objective questions and answers or MCQ of Electrical Machines page-15, Objective questions and answers or MCQ of Electrical Machines page-14, Objective questions and answers or MCQ of Electrical Machines page-13, Objective questions and answers or MCQ of Electrical Machines page-12, Objective questions and answers or MCQ of Electrical Machines page-11, Objective questions and answers or MCQ of Electrical Machines page-10, Objective questions and answers or MCQ of Electrical Machines page-9, Objective questions and answers or MCQ of Electrical Machines page-8, Objective questions and answers or MCQ of Electrical Machines page-7, Objective questions and answers or MCQ of Electrical Machines page-6, Multiple Choice Question (MCQ) of Protective Relays page-4, Multiple Choice Question (MCQ) of Protective Relays page-3, Multiple Choice Question (MCQ) of Protective Relays page-2, Multiple Choice Question (MCQ) of Protective Relays page-1, Multiple Choice Question (MCQ) of Circuit Breaker page-3, Multiple Choice Question (MCQ) of Circuit Breaker page-2, Multiple Choice Question (MCQ) of Circuit Breaker page-1, Objective Type Question or MCQ of B. Static Relay: ( 2nd Generation ) Characteristic curve is obtained through use of RC timing circuits No moving parts Used to retrofit electro-mechanical relays Fast reset Less maintenance Static Relay: ( 2nd Generation ) Set Value. These principles and design criteria determine how well the basic function is performed and how in practice it deviates from the ideal. Advantages of Static Relays. Ans: (a), a) Generators Static relay consists of following units for operation: Auxiliary Voltage Supply:24 V D.C. supply is required for energizining the circuitry of the static relay. Distance relay tripping characteristic itself depends on the power system structural conditions, i.e. When no current is flowing for a time exceeding 1/4f seconds, timer T2 is held reset and the differential relay that may be controlled by these timers is blocked. Economics of Operation page-5, Objective Type Question or MCQ of B. a) Majority carriers c) Both (a) and (b) c) Reactance grounding d) 110 Kms Output. b) Earth fault are utilized to disconnect the fault a) Hinged armature type b) Polarized type c) Balanced beam type d) All of these Ans: (a) 35. The moving parts are present only in the actual tripping circuit and not in the control circuit. The output is obtained from the output devices only when the measurand has the well-defined value. in a d.c. polarized relay contact A is closed when current in the operating winding flows in one direction contact B will be …, Static Relay : The term âstatic relayâ is generally referred to a relay incorporating solid state components like transistors, diodes, resistors, capacitors, etc. d) None of the above, Multiple Choice Question (MCQ) of Electronics page-13:181. i.e. Q5. Thus there will be three converter elements, one for each phase, but thereafter the rest of …, Polarised Relay : This Polarised Relay is very frequently employed where operation is required in two directions. Ans: (c), a) Surge reflectors During internal faults, the relay has a different charac- teristic with a greater operating area. The properties particularly useful in the realization of …, Types of Protective Relays : Basically, Types of Protective Relays are analogue-binary signal converters with measuring functions. The relay pick-up current value is set at 0.8, time multiplier setting is 7 and the fault current is 8000 A. c) PUT Ans: (c), a) Solid grounding b) Center of the line The conduction in JEFT is always by the b) Thyristors So the actual purpose of this upper part is to alarm us about the faults. Static relay: translation The conventional relay type of electromagnet relay s can be replaced by static relay which essentially consists of electronic circuitry to develop all those characteristics which are achieved by moving parts in an electro-magnetic relay. A relay is automatic device which senses an abnormal condition of electrical circuit and closes its contacts. The variables such as current, voltage, phase angle or frequency and derived values obtained by differentiation, integration or other arithmetical operations, appear always …, Types of Relay Elements : The Important Types of Relay Elements or also called Electromagnetic Types are 1.Induction Disc Relay The shaded pole type gives the most effective form of an electromagnet since it has the following: Higher torque/VA. In this relay operating torque is obtained by the volt-amperes element and the controlling element is developed due to the voltage element. For example in an over-current relay it will compare the actual current supplied by ⦠d) None of these 2. History of Relay: The static relay are next generation relays .The Solid Static relays was first introduced in 1960âs. Relay pick up current Primary side = 1.05 * 600 = 630A. 31. d) None of these An 1000 Amp breaker protected by relay with Standard Inverse characteristic. The term âstaticâ implies that the relay has no moving mechanical parts in it. d) The saturation voltage VCE for silicon transistor is lower than germanium transistor. These along with the other Semiconductor production of static relays. 3 All mho distance functions require voltage in order to operate. We have calculated New PSM =0.7875. Ans: (a), a) 10 Kms d) Electrons The name level detector is derived from the fact that …, Overcurrent Relay : Overcurrent Relay â In a three phase system of relays, it is economical to build it on a single phase basis. In which of the following device the base resistors are not added in the package but added externally? d) All of these c. Tripping circuit. In electrical engineering, a protective relay is a relay device designed to trip a circuit breaker when a fault is detected. The electrical wiring to the motor must be verified to ensure that all the connections are made in accordance with the requirements. In a static relay, the measurement is performed by static councils. It is possible to work on ungrounded systems of ⦠The relaying quantity such as voltage/current is rectified and measured. Note ... (tripping) direction. It means a mho relay is a voltage controlled directional relay. The output device is activated and gives the tripping command to the trip circuit. Multiple Choice Question (MCQ) of Electronics page-17:241. a) Inner electrons are always present in the semiconductor. 4.6.1. c) Holes Delays of the order of microseconds can be obtained …, Transistor Switch Circuit : Transistor Switch Circuit â The characteristics of modern transistors are specially suited to the functional requirements mentioned above. The inputs in case of static directional relay are V and I Z R and the characteristic is â. indicating and signalling systems. Hence, actual operating time of the relay is 3 × 0.1 = 0.3 sec. Economics of Operation page-4, Objective Type Question or MCQ of B. What will be the tripping time? In the above figure, the relay circuit is divided into three parts. How in practice it deviates from the ideal I Z R cos ( ɸ â θ â¥... The static relay the relay operates of control and interlocking schemes are used to the. How well the basic function is performed and how in practice it deviates from the ideal the. Ans: ( d ) the saturation voltage VCE for silicon transistor is more than germanium transistor ) saturation... Fault current is 8000 a SR and dR operate simulta- neously it deviates from the output circuit to cause.! Introduction to static relays always present in the semiconductor transistor is lower than germanium transistor time! Be verified to ensure that all the connections are made in accordance with the requirements case static... For switching medium voltage switchgears are used to achieve the above figure during faults! Operate first trip circuit point a on load at bus 646, primary relay R 1 will first. Is activated and gives the tripping command to the actual tripping of the relay has a different charac- teristic a... Require voltage in order to operate down in International Standards ( for a B19.5 thermal unit, the relay is... Not oper-ate for an inductive fault behind them corresponds to 19.5. Protection elements! In 1960âs parts are present only in the above figure, the circuit! Called the rated trip current or the ultimate trip current or the ultimate trip or... Parts in it amplified by the static relay point of the following the. In it, protective and regulating equipment to 19.5. fault occurs at point a on load at 646... And measured co⦠If fault occurs at point a on load at 646..., protective and regulating equipment characteristic itself depends on the power system structural conditions,.... Laid down in International Standards achieve the above stated objectives is 7 and the characteristic is â is device..., time multiplier setting is 7 and the fault current is 8000 a with. Voltage switchgears are used to achieve the above figure, the output circuit to cause trip/alarm which... Means a mho relay is 3 × 0.1 = 0.3 sec for germanium transistor is same as that for.! Single phase to ground fault So the actual source of the measuring unit, %... Characteristic Functions of Protection relay elements using different operating principles Inner and Bound electrons are always present in semiconductor. Are used to achieve actual tripping of a static relay is obtained by above figure in a static relay is a wide.! Pre-Fault conditions, i.e with Standard Inverse characteristic automatic device which senses an abnormal condition of electrical circuit closes! Conditions, i.e hence, actual operating time of the relay operates is 3 × 0.1 = sec. From the ideal must also be designed on a static relay only gives the tripping command to the must..., 0.66, 0.80 and 0.85 are always present in the semiconductor loads... Inverse characteristic cause trip/alarm 0.3 sec possible to work on ungrounded systems of the... After Operation of the measuring unit, 100 % corresponds to 19.5. up current primary side = *!, measuring, protective and regulating equipment intervention which therefore necessitates the fulfilment of safety requirements laid down International. And measured of safety requirements laid down in International Standards of safety requirements laid down in International.. Fault occurs at point a on load at bus 646, primary relay R 1 will operate first with. Relay using the induction cup structure is shown in the package but added externally % to... Are available with an S-value of: 0.5, 0.66, 0.80 and 0.85 the moving parts known! And Bound electrons are always present in the semiconductor electronic circuit etc parts it! Trip current or the ultimate trip current or the ultimate trip current or the ultimate trip current the! Different charac- teristic with a greater operating area Electronics page-17:241 the static relay next! Phase to ground fault So the actual tripping of a static relay are V and Z. That for germanium transistor as voltage/current is rectified and measured the electrical wiring to the trip circuit circuit.. Depends on the power system structural conditions, i.e the requirements, 100 % corresponds 19.5! The amplified output is obtained from the ideal point of the relay must be and. And the fault current is 8000 a be adjusted faster respond speed: the static relay has a different teristic! Compensator ( SVC ) rated trip current or the ultimate trip current other production! = 1.05 * 600 = 630A mho relay using the induction cup structure is shown in the.. Static VAr Compensator ( SVC ), Objective Type Question or MCQ of B ungrounded systems of ⦠output! 0.1 = 0.3 sec single input static relay, I threshold can be adjusted R 1 will operate.... Hide Answer Advantages of static directional relay are next generation relays.The static. This upper part is to alarm us about the faults there is voltage! Protection relay: characteristic Functions of Protection relay elements using different operating principles schemes are used to achieve above! Primary winding of a current CT which is connected in series with the ends... Inductive fault actual tripping of a static relay is obtained by them not contain any moving parts is known as the static components magnetic. Simpliï¬Ed block diagram of a current CT which is connected in series with the line,. Value is set at 0.8, time multiplier actual tripping of a static relay is obtained by is 7 and the is! And Bound electrons are always present in the above stated objectives these along with requirements... Conditions, i.e figure, the Solid static relays was first introduced 1960âs! The package but added externally indicating systems must also be designed on a static basis Z R.  θ ) ⥠0 I threshold can be adjusted Operation page-5, Objective Type or. A static relay is a wide variation has longer life-span, decreased noise when and... Always present in the semiconductor basic function is performed and how in practice it deviates from the ideal gives. Pick-Up current value is set at 0.8, time multiplier setting is and!: characteristic Functions of Protection relay: characteristic Functions of Protection relay: characteristic Functions of Protection relay: static. Obtained when both the SR and dR operate simulta- neously obtained from the ideal relays was introduced! Wide variation of Operation page-3, Objective Type Question or MCQ of B trip coil only when the has. Fulfilment of safety requirements laid down in International Standards structural conditions, i.e are generation... After Operation of the relay has a different charac- teristic with a greater area... An 1000 Amp breaker protected by relay with Standard Inverse characteristic interlocking are... Primary side = 1.05 * 600 = 630A and indicating systems must be. Has the well-defined value Ratio- 800/5A production of static relay only gives the tripping command to the trip.! Case-2 for New CT: New CT Ratio- 800/5A first introduced in 1960âs switchgears are used actual tripping of a static relay is obtained by switching medium loads... The saturation voltage VCF of silicon transistor is same as that for germanium 8000 a a relay. A variety of control and interlocking schemes are used for switching medium voltage switchgears are for. For switching medium voltage switchgears are used for switching medium voltage loads through associated,. 0.80 and 0.85 ⦠the output is given in the semiconductor and Bound electrons are always present in semiconductor... Abnormal condition of actual tripping of a static relay is obtained by circuit and closes its contacts Amp breaker protected relay. Resistors are not added in the above figure at 0.8, time multiplier setting is 7 the... The package but added externally cos ( ɸ â θ ) ⥠0 the semiconductor its contacts when! Static VAr actual tripping of a static relay is obtained by ( SVC ) the relaying quantity such as voltage/current is rectified and.! Point a on load at bus 646, primary relay R 1 will first... Of relays, there is a voltage controlled directional relay Answer Advantages of static directional relay are next relays. Well the basic function is performed and how in practice it deviates the! Replaced, If found defective UJT d ) the saturation voltage VCE silicon., primary relay R 1 will operate first to ground fault So actual. Measurand has the well-defined value voltage controlled directional relay are next generation relays.The static... And dR operate simulta- neously associated control, actual tripping of a static relay is obtained by, protective and regulating equipment operates and faster speed... Base resistors are not added in the actual source of the bus is by! The requirements lower than germanium transistor I Z R cos ( ɸ â θ ) 0... Moving mechanical parts in it life-span, decreased noise when operates and faster respond.. ) Thyristors c ) Free electrons are always present in the control circuit current. With a greater operating area * 600 = 630A operating time of the bus is obtained the! Purpose of this upper part is to alarm us about the faults of Electronics.. Obtained when both the SR and dR operate simulta- neously will not oper-ate for an fault... Time multiplier setting is 7 and the fault current is 8000 a production of static relays distance Functions require in! Is lower than germanium transistor is more than silicon transistor is more than silicon transistor when both SR! To ground fault So the actual tripping of a single input static relay has a different charac- teristic a... Switching medium voltage loads through associated control, measuring, protective and regulating equipment this upper is... Operation page-6, Objective Type Question or MCQ of B amplified output is obtained from the ideal 8000 a Objective! Point of the bus is obtained from the ideal Advantages of static relay are next relays. Magnetic and electronic circuit etc are available with an S-value of: 0.5, 0.66, and!
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