Abstract:
The invention relates to a system (11), which can provide reactive power in an alternating current network (10), the system comprising: a two-pole (12) having a first two-pole terminal (121) and a second two-pole terminal (122) having a reactance other than zero; a transformer (13) having an adjustable transmission ratio, comprising a primary side (17) having a first primary terminal (171) and a second primary terminal (172), and a secondary side (18) having a first secondary terminal (181) and a second secondary terminal (182); a switching device (14) for adjusting the transmission ratio of the transformer (13), wherein the first primary terminal (171) can be connected to a network line (101) of the alternating current network, the first secondary terminal (181) is connected to the first two-pole terminal (121), and the second secondary terminal (182) is connected to the second two-pole terminal (122).
Abstract:
The invention relates to an on-load tap changer (1) for controlling voltage, comprising semiconductor switching elements (61, 62, 71, 72), and to a method for controlling voltage for a variable transformer (2). The on-load tap changer (1) has a first load branch (6) and a second load branch (7) arranged parallel thereto. A partial winding (8) is arranged between the first and second load branches (6, 7). In the first load branch (6), a first semiconductor switching element (61) is provided upstream of the partial winding (8) and a second semiconductor switching element (62) is provided downstream of the partial winding (8). In the second load branch (7), a first semiconductor switching element (71) is provided upstream of the partial winding (8) and a second semiconductor switching element (72) is provided downstream of the partial winding (8). The on-load tap changer (1) consists of at least one switching module (5), which comprises the first load branch (6) and the second load branch (7) of the on-load tap changer. By timing the corresponding switch in the semi-conductor switching element and determining the flow path in the respective switching module (5), the switching loss and thus the development of heat are reduced.