Generator dual power supply switching logic

Let’s talk about the switching problem of security power supply. We have three hypothetical initial conditions, as shown in the figure (see attached figure 1 for details). Initial conditions 1-3. Condition 1 is that feeder switches 08, 09, 12, and 13 are in the closed position. Initial condition 2 It is feeder switch 01, 02 , 03 are in the closed position. The initial condition 3 is that the feeder switches 07 and 10 are in the closed position. Through the above initial conditions, we know that during initial normal operation, the working PC1 section operates with the security MCC1 section, and the working PC2 section operates with the security MCC2 section.

Generator dual power supply switching logic

Switching logic one: When switch 09 is tripped, the security MCC section 1 loses power. The switching logic will instantly trip switch 07 and delay switch 11. In this way, the security MCC section 1 is powered by the working PC section 2, completing a switch. The switch between the two sections is usually completed within 1-2 seconds, or less.

Switching logic two: When switching logic one is completed and the power supply is completed, switch 13 is tripped, and the security MCC section 1 loses power again. The switching logic will instantly trip switch 11, and at the same time send a start command to the diesel generator, and simultaneously send a command to close switch 05. When the diesel generator reaches the rated voltage, the diesel generator outlet switch is automatically closed, thus completing the second switching, and the diesel generator replaces the working PC2 section to supply power to the security MCC1 section. Due to the different characteristics of diesel generators, the switching time usually takes more than ten seconds. Generally, from a safety perspective, more than ten seconds is enough. In some power plants, the switching time may reach more than 20 to 30 seconds. , then it is estimated that the important equipment below will jump into one piece.

Switchback logic one: close switch 13. The switching logic will jump to switch 05 instantaneously and switch 11 after a delay. The security MCC section 1 has completed the conversion from the diesel generator power supply to the work PC section 2 power supply. In the switching logic, the diesel generator often does not have a stopping logic, and we can just stop it manually.

Switchback logic two: close switch 09. The switching logic will jump to switch 11 instantaneously and close switch 07 with a delay. The security MCC1 section has completed the conversion from the working PC2 section power supply to the working PC1 section power supply.

It is worth noting that during the switching process, the switching logic is to determine the voltage of each segment. When the corresponding switch is tripped or closed, the switching logic will first determine whether the voltage condition of the segment to be switched is met, and then the subsequent steps will be executed if it is met. I'm talking about switching programs.

Here we only talk about the switching logic of security MCC segment 1. Security MCC segment 2 is similar to segment 1 and will not be discussed again. You can also refer to the switching logic of the automatic switching device.