| 摘要 |
1. The control and earth leakage protection system for a mining transformer station contains disconnecting switches and connecting switches on the primary and secondary sides of the power transformer, and an earth leakage protection, a leakage protection and line testing system on the secondary side. It also contains a control and signalling block. It is characterised in that the earth leakage relay (6.2) of the earth leakage protection is connected to the secondary voltage winding of the power transformer (3) through the ground fault system (6.1) connected in series and equipped with the current sensor (6.3). The cut-out relay (7.2) of the central leakage protection is connected through the inductive choke (7.4) and the connection assembly (7.1) to these windings. The output of the relay is connected to the input of the warning relay (7.3) of the leakage protection. The line test switch (7.8) is connected between the connection assembly (7.1) and the cut-out relay (7.2). The measurement circuit of the interlocking relay (8.2) of the blocking leakage protection is connected through single-phase choking coils (8.4) to leakage lines. The chocking coils are connected through the resistor (8.7) to the line test switch (8.6) and through the high-voltage feeder (9.1) to the static measurement-and-control relay (9.2) of the line testing block. Connecting switches (2.4) and disconnecting switches (1.5), equipped with an interlocking device, are connected to the primary and secondary sides of the power transformer (3). The interlocking device makes it impossible to open the disconnecting switches (1.5), when the connecting switches (2.4) are closed.
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