IEEE Std 1870 pdf free download

IEEE Std 1870 pdf free download.Parameter Measurement of AC Transmission Lines.
5.5 Instruments for dc resistance measurement
The instrument to obtain the dc resistance ofa transmission line can be a special instrument or the combination
of a dc power source, a dc voltmeter, and a dc ammeter.
The dc resistance tester can be used, and its class of accuracy should be within 0.5. Alternatively, for the combined measuring instrument for dc resistance, the power source can be several batteries connected in series, and the class of accuracy of the dc voltmeter and ammeter should be within 0.5.
6. General considerations during measurement
The following items should be considered before conducting off-line measurements:
a) Make sure that all the temporary grounding wires along the line are dismantled and nobody is working on the transmission line.
b) Pay close attention to the weather condition along the lines during the measurement. The measurement shall he stopped if the weather is not suitable for measurement, for example. when there is thunderstorm, rain, or snow along the transmission line.
c) The leads of shunt reactors, capacitors, and capacitive voltage transformers (CVTs) should be disconnected from the transmission line in the off-line measurement. The transmission line shall be disconnected from bus-bars.
d) Any series compensation device used in the transmission line shall be bypassed during the measurement.
e) If the transmission line under measurement is composed of cables and overhead lines, it is recommended to measure the parameters of the overhead lines and cables, respectively.
1) The substation grounding grid should serve as protective grounding. neutral point grounding. and short-circuit grounding. The grounding point of a tower is prohibited to be the grounding point of the measurement.
7. Measurement of induced voltage and current
7.1 General
If there is any energized ac transmission line close to the transmission line to be measured, the mutual inductance and coupling capacitance may lead to a high induced ac voltage on the line to be measured. When both terminals are grounded. a large induced ac current may emerge on the line to be measured. If there is any dc transmission line nearby, a high induced dc voltage may appear as well.
Before the measurement, the induced voltage and current should be estimated according to Annex A, and then the voltage dividers, voltmeters, and ammeters with suitable ranges are selected.
8. Phase verification and insulation resistance measurement
8.1 General
Phase verification and insulation resistance measurement arc performed when all the conductors are not in
service.
Phase verification is adopted to check the consistency of phase labels at both terminals, so as to prevent the power system from serious impacts when the transmission line is switched into service, especially for newly built or reconfigured lines.
The insulation resistance measurement is adopted to check whether any protective grounding wire has been dismantled along the newly built or reconfigured lines.
8.2 Phase verification using dc (or ac) power sources
DC power sources are recommended to be used for phase verification if the induced voltage of the measured line is about several hundred volts. Take the phase verification of phase e as an example. The procedures are as follows.IEEE Std 1870 pdf download.