This article recounts a10kV substation bus voltage anomaly incident, analyzes its root cause of auto-backup not exiting, and proposes preventive measures like regulation updates and training. In September 2023, as a front - line fault maintenance worker, I detected abnormal voltage on the 10kV Section I bus of a substation during monitoring duty and informed the operation and maintenance team. The monitoring system showed: U0 = 0 kV, Ua = 6. 05. Get %Z from nameplate or Table 1. Transformer impedance (Z) helps to determine what the short circuit current wi l be at the transformer secondary. With the rapid development of the. That gives an answer in ohms, so to continue we need to convert the % impedance of the transformer into an ohmic value. 1 kA -> Voltage L-L / [root 3 * (Zup_LV + Ztr)]. (MVA at LV. Abstract: In the distribution network, the single phase grounding fault of potential transformer (PT) caused by burning phenomena occur.
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