| 摘要 |
It is presented a compensating system (1) for a power system (2). The compensating system (1) comprises a compensator (3) comprising semiconductor switch means, which compensator (3) has phase legs (6-1, 6-2, 6-3) which on a first side (13) of the compensator (3) defines AC inputs for connection to a respective phase (11-1, 11-2, 11-3) of the power system (2), wherein the phase legs (6-1, 6-2, 6-3) are connected in wye connection at a second side (15) of the compensator (3), which wye connection has a neutral point (N); and a filter arrangement (9) which at a first side thereof is connected to the neutral point (N) of the wye connection and at a second side is connected to the AC inputs to thereby form a circuit (10) with the compensator (3), wherein the filter arrangement (9) is arranged such that the circuit (10) acts essentially as an open circuit for positive sequence currents or voltages and negative sequence currents or voltages, and as a closed circuit for zero-sequence currents, wherein the filter arrangement (9) is further arranged to block a zero-sequence current having a fundamental frequency and to allow a harmonic of the zero-sequence current to pass therethrough, whereby the harmonic of the zero-sequence current is able to flow through the closed circuit. |
