Questions regarding 10/0.4KV substation transformation
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Problem description: In the 10/0.4KV substation, the DC panel is not powered. The 10KV incoming line switch was manually energized and closed to supply power; the PT cabinet’s trolley is in the operating position. Can the voltage of the 10KV bus be displayed? Why? I would appreciate some advice from those who are more experienced; thank you
For electrical work, it is essential to be familiar with the principles of circuit diagrams; those who do not possess a qualified electrician’s license must never attempt such work on their own. Should I learn the procedures (the three rules and one system) first, or should I understand the circuit diagrams thoroughly first? (I’m not an electrician; it’s just a suggestion.)
It depends on the specific cabinet and the detailed secondary schematic to determine whether it can be seen or not. If a digital display is used, or if it is viewed on a comprehensive protection device or smart meter, it should not be visible. Previously, on our PT trolley, which was located in front of the incoming line switch (under the main incoming line cabinet), a pointer-type voltmeter was used to display the voltage; as long as the incoming line was powered, the voltage could be seen whenever the PT trolley was in its working position. It is recommended that for the first power-up, the equipment manufacturer should be present to conduct inspections according to their procedures before powering it on. Safety first.
A pointer voltmeter will definitely show the reading; multi-functional digital meters generally measure alternating current and thus can display the value, while comprehensive protection devices work with direct current, so they cannot show a reading
This post was last edited by Seawater Desalination_IYAT on 2018-4-15 at 20:41. I don’t get it; can one actually see the bus voltage or not? Could you explain in detail whether the bus voltage display shows AC voltage from a multi-functional digital display or DC voltage from a comprehensive protection system? Thank you
Uh, it can be seen； There is voltage on the AC bus (100V AC); both the voltmeter and the multimeter can show this voltage. The PT cabinet usually has a voltmeter as well
Under normal circumstances, if a voltmeter is installed on the PT cabinet, the voltage can be measured as long as the 10kV incoming switch and the PT cabinet are in operation.
If the voltage signal reaches the voltmeter on the PT cabinet or the computer system in the control room, and the wiring is correct, then the voltage can be measured as long as the 10kV incoming switch and the PT cabinet are operating. This has nothing to do with the DC power supply, unless the measuring instruments use power from that DC supply.
Thank you to all the teachers for their responses; I’ve learned a lot, thank you