IEEE C37.100.2-2018 IEEE Standard for Common Requirements for Testing of AC Capacitive Current Switching Devices over 1000 V.
4. Design tests 4.1 General The tests in this standard are designed to be used by other standards to demonstrate a capability of a particular device to switch capacitive circuits. Not all devices need be tested to all of the tests in this standard. Any device can be qualified for any given capacitive circuit in this standard with no requirement to perform the other tests. The capacitive current switching abilities of a device shall be stated in terms of the ratings given in 4.2. 4.2 Ratings and applicability 4.2.1 Rated capacitive switching current The rated capacitive switching current is the rms symmetrical value of the capacitive load current that a device is required to make and break under specified ratings. 4.2.2 Rated maximum voltage (V) or (U r ) The rated maximum voltage indicates the upper limit of the highest voltage of systems for which the capacitive current switching device is intended. 4.2.3 Rated power frequency (f r ) The preferred values of the rated power frequency are 50 Hz and 60 Hz. 4.2.4 Rated application grounding condition The rated application grounding condition is the connection made between the neutral of a wye-connected capacitor bank and the ground. The connection is typically referred to as “grounded” or “ungrounded”. A capacitor bank neutral grounded with a high impedance, such as a potential transformer or voltage divider, is considered to be ungrounded. A delta-connected bank is ungrounded.
4.2.6 Rated restrike performance The following three classes of capacitive current switching devices are defined according to their restrike performance: a) Class C2: Very low probability of restrike during capacitive current breaking as demonstrated by specific tests (Table 3 or Table 5). b) Class C1: Low probability of restrike during capacitive current breaking as demonstrated by specific tests (Table 4 or Table 5). c) Class C0: Unspecified probability of restrike during capacitive current breaking. Applicability of rated restrike performance Tests are conducted to demonstrate the rated probability of restrike at or below the following capacitive switching currents. Various product standards refer to these values as rated values. a) Rated line-charging breaking current (LC) b) Rated cable-charging breaking current (CC) c) Rated capacitor bank breaking current (BC) NOTE—In most cases, the ‘rated’ capacitive switching currents LC, CC, and BC do not reflect a limit of the capacitive switching capability of the device, rather the level at which the rated probability of restrike performance has been proven by test. Hence, it is not unusual for a single device to be rated Class C2 for line-charging current at one value but Class C1 for a higher level and again Class C2 for some intermediate value of capacitor bank breaking current.IEEE C37.100.2 pdf download.