IEC 60270:2000 pdf download.High-voltage test techniques Partial discharge measurements.
IEC 60270
— defines the terms used;
— defines the quantities to be measured;
— describes test and measuring circuits which may be used;
— defines analogue and digital measuring methods required for common applications;
— specifies methods for calibration and requirements of instruments used for calibration;
— gives guidance on test procedures;
— gives some assistance concerning the discrimination of partial discharges from external interference.
The provisions of IEC 60270 should be used in the drafting of specifications relating to partial discharge measurements for specific power apparatus. It deals with electrical measurements of impulsive (short-duration) partial discharges, but reference is also made to non-electrical methods primarily used for partial discharcie location (see annex F).
3.5
specified partial discharge magnitude
largest magnitude of any quantity related to PD pulses permitted in a test object at a specified voltage following a specified conditioning and test procedure. For alternating voltage tests, the specified magnitude of the apparent charge q is the largest repeatedly occurring PD magnitude
NOTE The magnitude of any PD pulse quantity can vary stochastically in successive cycles and also show a general increase or decrease with time of voltage application. The specified PD magnitude, the test procedure and also the test circuit and instrumentation should therefore be appropriately defined by the relevant technical committees.
3.10
digital partial discharge instruments
considered in this standard are in general based on analogue measuring systems or instruments for the measurement of apparent charge q, followed by a digital acquisition and processing system. The digital part of a digital PD-instrument is used to process analogue signals for further evaluation, to store relevant quantities and to display test results. See also annex E.
NOTE A digital PD-instrument can also be based on a coupling device and a digital acquisition system without the analogue signal processing front end.IEC 60270dard does not provide specific information applicable to this type of instrument.
3.11
scale factor k
factor by which the value of the instrument reading is to be multiplied to obtain the value of the
input quantity (IEC 60060-2:1994, 3.5.1)
6.3 Calibrators for performance tests on measuring systems
For checking additional features of the test circuit and measuring system characteristics, a more sophisticated calibrator device or even calibration procedure is recommended. The following characteristics are recommended for a calibrator used for performance tests:
— variable charge magnitude q0, in steps or continuously, for determination of the linearity of the scale factor k. The variation should be achieved by varying the step voltage. The linearity of the calibrator should be better than ±5 % or ±1 pC, whichever is the greater;
— variable time delay between two consecutive pulses of the same polarity to check the pulse resolution time Tr of the measuring system alone or the pulse resolution time of the whole test circuit;
— both output terminals of the calibrator floating, i.e. potential-free output;
— for battery-operated calibrators a battery status indicator should be provided;
— bipolar pulses to detect a change in apparent charge magnitude measurement with respect to PD current pulse polarity;
— a series of calibration pulses with known number of equal charge magnitudes and rrntition frnuncv N In r.hcr.k diciitM rnirtil dishra instruments.IEC-60270-2000