IEEE C37.103-1990 pdf free.IEEE Guide for Differential and Polarizing Relay Circuit Testing.
IEEE C37.103 shorting switch is usually found mounted on the test jack. The purpose of this switch is to dis-connect the current coil of the device to be tested from the current circuit or CT secondary.As its nameimplies, it does this by first shorting the source-side circuit and then disconnecting the load-side circuit bymeans of make-before-break contacts. This operation bypasses and open-circuits the device to be tested.Animportant point to remember is that this switch does not ground the CT.Also, depending upon the switchconfiguration, total isolation of the load-side circuit may require insertion of a “dummy”test plug in the testjack. With the switch in the shorted position, a closed current circuit still exists. When a test plug is insertedinto the test jack without the shorting switch operated, the circuit from the test plug must be completed inorder to keep the CT circuit closed.
The relays should have been tested in accordance with the manufacturer’s instructions and the IEEE PESSpecial Report No.96TP115-0-1996 prior to the testing of the circuits by primary or secondary injection.
This type of test set derives its test voltages and/or currents from a variable autotransformer and loadingtransformers. The technique is especially useful in high-current testing since the test currents are developedwith a lower test voltage, thus reducing the input power requirements for the test source. The output is rela-tively constant at a low voltage, and therefore,may be subject to some current wave-shape error. This isminimized by using the lowest current output tap (highest source voltage) that will deliver the required testcurrent for the required time duration.
The resistance box consists of switched resistance units and a variable resistor. It is connected in series witha suitable test current source and the relay under test.The test source must be capable of supplying therequired current.The current wave shape is good since the resistance is usually more than the nonlinearimpedance of the load.IEEE C37.103 pdf download.