High-voltage inverter commutation

Are commutation failures a threat to high-voltage direct current inverters?

With the increasing applications of high-voltage direct current inverters in heavy-load grids, commutation failures (CFs) pose a severe threat to the safe and stable operation of power systems. This study first sorts methods of CF inhibition into different categories and then investigates their effectiveness, adaptability and limitations.

When does a yd inverter fail to commutate?

When the commutation first occurs in the YY inverter, it’s assumed that the commutation failure first occurs in the commutation of V12 to V32. Since the short-circuit path is formed when V42 is conducted, the YD inverter will fail to commutate during the commutation of V21 to V41. The commutation process is shown as Fig. 7 (a).

What happens if an inverter fails two consecutive commutation times?

If the inverter fails two consecutive commutation times or more, it is called continuous commutation failure, and vice versa is called one commutation failure. The problem of commutation failure discussed in this article is a commutation failure. The converter valve is composed of semi-control device thyristors.

What is the commutation area of an inverter?

In normal operation, the inverter side has α + μ + γ = π, and the commutation area is S1. In the event of a fault, the voltage amplitude of the commutation bus is reduced, and the commutation area is S1′. When S1 = S1′ and the firing angle remains the same, the commutation time will be extended.

What happens if a DC converter fails commutation?

When a fault causes a commutation failure in the DC system, the short circuit of the upper and lower arms of the inverter will cause a sudden increase in DC current. By detecting the change law of the DC current Id at the outlet of the rectifier, it can be diagnosed whether the converter has failed commutation.

What causes commutation failure?

Commutation failure is one of the most common faults in the operation of high voltage direct current transmission (HVDC). This paper analyzes the influence of voltage amplitude reduction, zero-crossing displacement, and voltage waveform distortion on the commutation...