Regarding full-voltage starting of high-voltage motors
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I’ve been feeling a bit disappointed lately to see so few people participating in discussions or offering insights on the topic of high pressure. Since it is inevitable for large chemical companies to use high pressure in their new installations, electrical technicians often lack sufficient knowledge in this area. I hope everyone can actively discuss topics in this area. First, I would like to share some personal opinions, and I hope my colleagues will feel free to offer their guidance: The power supply characteristics of motors that are started directly at full voltage using a 10KV common bus are as follows: 1. A relatively high voltage level on the motor start bus is required; it should generally be no less than 85%, meaning that the voltage drop in the power supply system should not exceed 15% ； 2. The voltage at the motor terminal is high, approximately equal to the bus voltage (with only a difference of 1–2%), resulting in a large starting current and a short starting time ； 3. Suitable for situations where the motor capacity is relatively small while the busbar short-circuit capacity is large ； 4. Requires the fewest devices, resulting in the lowest investment. It should be preferred when meeting the bus voltage drop requirements. In practical engineering applications, this power supply method can be further divided into two scenarios: 1. Powered by the 10KV bus of the equipment substation ； 2. Powered directly from the 10KV bus of the factory’s main substation or sectional substations; an independent bus section and switching equipment are installed at the device substation or the main fan room ； This power supply method is often used when the motor capacity is large, especially when there are current-limiting reactors on the outgoing lines of the main substation. Application determination for full-voltage direct start: This method can generally be used when the rated capacity of the motor is less than or equal to 3–3.5% of the short-circuit capacity on the power supply bus.
Not bad; currently, high-voltage cabinets are being installed at the construction site, so it’s a good opportunity to learn something
Application determination for full-voltage direct start: This method can generally be used when the rated capacity of the motor is less than or equal to 3–3.5% of the short-circuit capacity on the power supply bus. Does the original poster have any evidence for this?
Agree with what was said on the 4th floor. Does the original poster have any evidence?
When the motor power exceeds 20% of the power capacity of the power supply, whether it is a high-voltage or low-voltage motor, it is necessary to check the bus voltage level during startup. The verification of the bus voltage during motor startup can be divided into: (1) the voltage verification when a single motor with the highest power starts normally; (2) the verification of the bus voltage level when motors are started in groups. Case (2) can further be divided into several sub-cases.
Our facility has a 6300KW high-voltage motor that is started using a water bath.