In carrying out my invention in one form I modify the relay previously described by providing a control means for activating its integrator as soon as a miniumum overcurrent condition is reached and for later delaying the resetting action of the integrator whenever the current subsides below the minimum overcurrent level. These developments have produced changes in the way they are applied from electromechanical (EM) relays and, further, offer many new features to provide greater utilization than previously possible. The control means 3 comprises a pick-up control circuit 32 in combination with a reset control circuit 48. Operational amplifier 50 has a feed-back path between its output terminal and its inverting input terminal consisting of a first branch containing resistor 55 in series with diode 56 and a second parallel branch containing diode 57. 0000001126 00000 n
0000001146 00000 n
The electrostatic discharges mean sudden flows of electrons between the charged objects. These relays have earned a … The term "high speed" connotes operation in less than approximately 0.1 second and usually in 0.05 second or less. One particular application in which delayed reset is desired is in the protection of three-phase AC electric power generators from unbalanced phase currents. are required to construct this protective relay.. If the input signal were a pulse train whose frequency varies with the square of current (see U.S. Pat. Thus signal 17 is a train of undulating half cycles the amplitude of which is proportional to the negative phase sequence current. A solid state protective device is disclosed which protects electrical apparatus from heat damage due to overcurrents, particularly one which protects electrical generators from damage caused by heat due to excessive negative phase sequence currents. References. 0000000766 00000 n
25,762--Kotheimer. overcurrent relays should be used over a limited length in the 3 feeder sections. Selected pages. d. means connected to said integrating means capable of producing a trip signal when said output signal exceeds a preselected magnitude. It protects the equipment of the power system from the fault current. These over-current relays need to coordinate with each other such that the relay nearest fault operates first. A protective relay as defined in claim 9 in which said accumulator comprises a capacitor the charge on which increases with time whenever the accumulator is operative, said accumulator being in its quiescent state whenever the charge on said capacitor is near zero and attaining its trip state when said charge increases to a preselected level. time current characteristics of static over current relay, components of instantaneous over current relay, instantaneous over current relays. If a second overcurrent condition were to occur while the delayed resetting action is still in progress, the integrating action will resume with a residual charge on the energy storage element, whereby a relatively shorter time is required for the integrated voltage to reach the same reference level at which the trigger circuit is energized. di Musiani Franco & C. Siemens Ag, 1000 Berlin Und 8000 Muenchen, De. The second option is to install overcurrent devices in both the primary and secondary circuits of the transformer. In the accumulator 2, the output voltage of integrator 22 is monitored by the level detector 60, and when this voltage has increased to a predetermined magnitude a trip signal 62 will be emitted which causes the trigger circuit 64 to produce an appropriate response signal 65 which may be used to open a circuit breaker or activate an alarm or warning device (not shown). (1 relay can be used as over current only for under voltage we use another relay). )��A�T{���ֺ{������n��|?_����!�����ߵ�|��|�M���[�������u�w���?���6���_}M��߯��}�����v����Z��w ��\�)e����N��W}�w����p�g���}��*�I]�q�x����I�����} �c�<5�+�X0��K����UW�~��?a��{��
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[��m���Wj������K����f���c�#��Ta0�`���S�D�`�DDB"�`��� �E�X�%SD� `�A�� 0~ �� `xn? US Patent References: 3849706: LOGARITHMIC COMPUTING CIRCUIT: 1974-11-19: Johnson et al. Thus, it has a adjustable time setting as well as a pick up adjustment. 1. This operational amplifier has a feed-back path containing capacitor 42. In this option, the secondary device must be rated no more than 125% of rated current of the transformer and the primary no more than 250%. Accordingly, it is an object of my invention to provide an improved static overcurrent relay having a linear reset characteristic which matches an approximately linear cooling curve of the electrical apparatus to be protected. No. LA PUNTIMATIC S.n.c. The output of pick-up control circuit 32 is supplied through a resistor 44 and a diode 46 to the reset control circuit 48. Directional time-overcurrent relay 1MRK 509 025-WEN Version 2.1 Replaces - 1MRK 509 025-WEN Page 2 ABB Network Partner AB Version 2.1 SETTINGS: All settings can be changed while the relay is in normal service. For The Measurement Or Comparison Of Electrical Quantities. In a typical application the over current relay is used for over current protection, connected to a current transformer and calibrated to operate at or above a specific current level. Generally, inverse-time overcurrent protective relays respond to the magnitude of a circuit quantity such as alternating current or its negative phase sequence component, for example, becoming excessive. Static over current relays • The output of this summation C.T is fed to an auxiliary C.T. g`b`�� �� 06��c��x\b��+w��wܙ=����,�ya�z-~9$�X���A����@���Ao@� ���
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A protective relay as defined in claim 1 in which said integrating means comprises a first operational amplifier across which is connected a feed-back loop capacitor. This delay is fixed and it is independent of PSM value. If the negative phase sequence current increases above a predetermined pick-up level, the output voltage of the function generator is integrated, and after a delay determined by the time required for the integrated voltage to reach a preset reference level, a trigger circuit is energized causing the required protective action to be effected (e.g., a circuit breaker is opened or an alarm is sounded). This relay has to be installed straight only and away from magnetic field. As the name implies, these relays do not contain any moving parts. Negative voltage source 35 produces at the non-inverting input of operational amplifier 34 a small reference signal whose magnitude depends on the values of resistances 36, 38, and 40. In this relay, a symmetrical component segregating network derives a voltage signal proportional to the negative phase sequence current in the stator windings of the protected generator, and this signal is rectified and applied to the input of a non-linear function generator which produces an output signal, the magnitude of which varies approximately with the square of the input signal. Name the different kinds of over current relays. This invention will be more fully understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawing, the single FIGURE of which is a schematic circuit diagram of a relay embodying a preferred form of the present invention. Abstract: The technology of static overcurrent relays has developed very rapidly in the past few years. While I have shown and described one form of my invention, modifications will surely occur to those skilled in the art. 4. H�b```e`` Relay operate immediately when overcurrent is present. Over the past decades, static relays were used, while nowadays microprocessor relays are used. La Puntimatic S.N.C. relays that operate in a minimum time of approximately 0.1 second. Define operating time of a relay. The directional relay is nothing but a directional power relay which operates when the power in the circuit flows in a particular direction. Pick-up control circuit 32 will keep the integrator 22 inoperative until the negative phase sequence current exceeds a predetermined critical pick-up level. These developments have produced changes in the way they are applied from electromechanical (EM) relays and, further, offer many new features to provide greater utilization than previously possible. Contents. GENERAL INTRODUCTION TO STATIC RELAYS . 11. 1 relay can perform only 1 function. Testing and maintenance of protective gear, Protection against surge … Static Relays : Development and classification of static relays, Different types of phase and amplitude capacitors, Basic static relays used in protective scheme, Elementary idea about digital & numerical protection. This is the aforesaid "trip state" of the accumulator 2, and the rate at which it is attained varies with the average magnitude of the signal at the input terminal 19. Over-current relays can be used to protect practically any power system elements, i.e. Over the past decades, static relays were used, while nowadays microprocessor relays are used. No. In the illustrated embodiment of my invention, the function generator 18 approximates a squaring function and produces at a terminal 19 a relatively negative modified input signal which is proportional in magnitude to approximately the square of the signal 17. data:image/svg+xml;base64,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, data:image/svg+xml;base64,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, GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER, EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS, Emergency protective circuit arrangements responsive to undesired changes from normal non-electric working conditions using simulators of the apparatus being protected, e.g. Gives an output signal in the art in fig power relay which operates when load... 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