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This paper presents the graphical analysis and design considerations of multi-input sine comparators whose mathematical analysis has already been presented in an earlier paper by the authors (Anti Kumar and Parthasarathy 1967). Particular emphasis is placed on the design of a circuit, using semiconductor components, which provides a quadrilateral polar characteristic on the impedance plane. Novelties of design include a reactance reach, increased tolerance to fault resistance as the fault point moves towards the relay location, directional feature and independent control of each line segment constituting the quadrilateral, so that the fault area and tho relay characteristic could be closely matched. Test results show the negligible transient overreach and a constant operating time which is 1 1/2 cycles or less, and irrespective of fault location. The flexibility of design enables it to be used as a three-zone stepped time-distance relay or in conjunction with pilot schemes.
Test results show the versatility of the unit and the flexibility of the comparator theory. By suitable modifications of only the input signals, any desired characteristics can be easily obtained as dictated by system requirements. Special care has been taken to use similar switching blocks so that replacement is rendered simple. [ABSTRACT FROM AUTHOR]

The use of dual comparators for offsetting the transient overreach effects of distance relays is quite popular. Two schemes of static dual comparators, involving powerful and versatile digital and analog techniques, are developed and tested. The introduction of those circuits may help to achieve the more stringent requirements for protection of modern interconnected power systems.
(1) The presence of transients in one or both of the inputs V and V to the coincidence circuits is dependent on the type of measuring circuit used to get the desired distance characteristic. The relay performance is not influenced by transients in any case.
(2) The time of operation of the relay is dependent on several factors and it will be 1 to 3 cycles for most of the power system faults. Actual tests have not been carried out since it is felt that several test results reported on similar comparators will also hold good in this case.
(3) Although the above schemes utilize established criterion of dual comparison an attempt has been made to provide alternative approaches in circuitry with an eye on economy considerations. This paper also introduces to the static relay field the more powerful and versatile digital and analog techniques which may remove several simultaneous switching problems encountered in switched distance and multi-zone schemes. [ABSTRACT FROM AUTHOR]

Examines the sequence detection relay with quadrilateral characteristic. Determination of the drawbacks of sine type phase comparators; Effects of polarization on comparator yielding characteristic; Analysis of the quadrilateral characteristics of phase to phase fault relays.

Presents a mathematical analysis on obtaining ratio of time-varying voltages of radio meters for process instrumentation. Illustration of the block diagram; Construction of comparator circuits; Increase in voltage across charging condensers.

The article focuses on the cryogenic current comparator (CCC) developed by the National Physical Laboratory.