DE1938396A1 - Converter arrangement - Google Patents

Description

19383S6

MANNHEIM BROWN BOVERI

Mp.-Hr. 622/69 Mannheim, July 23, 1969

Pat / P / Bu.

"S rectifier arrangement"

The invention relates to a Stromrichteranordnuhg with at least two converters connected in series on their direct current side, preferably with thyristor valves are equipped. A bypass switch is connected in parallel to each partial converter. Also serves a special device according to patent application P 16 13 718.1 for protection against incorrect switching operations.

The converter arrangement according to the main patent is to a bypass valve connected in parallel to each partial converter; the said protective device is activated by the switching movement of the bypass switch influences and triggers the ignition of the corresponding bypass valve. She turns out to be in high-voltage direct current transmission (HVDC) systems that are equipped with mercury vapor valves, as very advantageous. In the case of re-ignition, which occurs relatively frequently, an explanation can be provided very quickly and be done without the aid of mechanical switches by the bypass valve is ignited. This causes the main valves, which are heavily stressed by the re-ignition current, to become temporarily relieved and can recover. A return commutation then takes place after a few hundred milliseconds the power to the main valves and normal operation is restored.

Lately the signs are increasing (ETZ-A, Vol. 89 · (1968) H.8; AEG-Mitt., 56 (1966) 6, p. 408, left column; Bull. SEV 58 (1967) 2, Jan. 21, p. 60, right column),

μ 2 - 009887/0961

- 2 - 622/69

that shortly with the use of thyristor valves, i.e .. controlled semiconductor converters in the HVDC can be expected «One of the main advantages is mentioned that with thyristors at normal operating voltage no backfires, i.e. no temporary loss of the Blocking ability, occur. For this reason, partial converters connected in series require those with thyristor valves are equipped, also no bypass valves.

The bypass switches are necessary, however. To the domestic and To enable a single partial converter to be taken out of operation, a bypass switch is provided, which initially bridges the relevant partial converter. Would this bypass switch can be bridged by a partial converter operating in rectifier mode without any special measures leave, a short-circuit current would result, to which thyristors in particular are very sensitive. It offers therefore, according to a method known per se (Direct current, Nov. 1965, p. 164) initially the current to commutate to two main valves connected to a common three-phase supply line and thus the same To achieve the same effect as when igniting a bypass valve. In this state, which is called here by-way operation, the bypass switch can then be operated safely.

Of course, it is not init even with such an arrangement To exclude safety that the bypass switch is actuated unintentionally. Because of the overcurrent sensitivity the thyristors even cause a particularly dangerous malfunction

The object of the invention is to provide the aforementioned arrangement according to the main application for protection against incorrect switching operations of the bypass switch on converter arrangements without bypass valves ι preferably with thyristor valves,

- 3 -009887/0961

Pnt 4 F I (868th MOO / EA)

- 3 - 622/69

apply. According to the invention, this object was achieved by that the protective device of the converter arrangement of the type described above is one of the Sohaltbewegung of the bypass switch operated immediately at the beginning and before the closing of the bypass switch main contact Contains device that affects the control device of the associated converter converter so that a Known bypass operation of two valves of the partial converter connected to a common three-phase line arises.

Nothing changes in the applicability of the invention if a special quick disconnector is used as a bypass switch or load switch is used.

In the drawing, an embodiment of the invention is shown, which is described below.

A transformer 1 feeds through two three-phase secondary windings 2 and 3 and two partial converters 4 and 5, which are constructed as three-phase bridges and connected in series, a direct current network with the rails 6 and 7. Parallel to the converter bridge 4 is a bypass switch 8. Likewise a bypass switch 9 is parallel to the converter bridge 5. The connection point of the two part converters is earthed.

The control of the individual valves of the converter bridges and 5 takes place via a control device 10, the necessary to bridge the potential differences between the control device 10 and the individual valves Devices such as magnetic pulse transmitters with corresponding winding insulation are not shown in the figure. This control device 10 is available with two devices

- 4 0098 87/0961

! '«Ι 4 F I (Β'Λ WOO / FA)

- A - 622/69

11 and 12 in connection, for the mechanical switches here are used. These two switching contacts 11 and 12 are influenced by the associated bypass switch 8 and 9, respectively. They are in the immediate vicinity of drive devices 15 and H of the bypass switches 8 and 9 and with this on the same potential, as the figure shows on earth potential. The message that the circuit breaker 8 or 9 closes, takes place immediately after the start of the closing movement and a long time before the actual closing of the Bypass switch main contact via the associated signal line on the control device 10,

The control device 10 ensures the ignition sequence necessary for the transition of the thyristor valves to bypass operation. The current can commutate to the two thyristor valves. The bypass switch can therefore also be used in the event of unintentional Switching operations can be operated safely.

009887/0961

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Claims (1)

- 5 - 622/69 claim Power converter arrangement with at least two partial power converters connected in series on their direct current side, preferably equipped with thyristor valves with a bypass switch for each partial converter connected in parallel, and with a protective device against incorrect switching operations Patent application P 16 13 718.1, characterized in that that the protective device is one of the switching movement of the bypass switch directly at the beginning and before the closing of the bypass switch main contact contains actuated device, which influences the control device of the associated partial converter so that an on, - known By-pass operation of two valves of the partial converter connected to a common three-phase line arises 009887/0961 Blank page