Currently widely used on-load tap changers (OLTC) have insufficient reliability and short service life. Development and implementation of electronic OLTC on photothyristor cells will significantly improve the reliability of the transformer. However, building the OLTC on the primary side of a 110 kV transformer is practically impossible, and there is no taps on its secondary side. The solution is to use an auxiliary transformer in combination with booster transformers. Existing structures are considered and an improved design of the OLTC is proposed, allowing increasing the number of control steps with the minimum number of cells. An original thyristor state sensor, required for the OLTC control system, is proposed.
Volume 11 | 05-Special Issue