SU1347115A1 - Method of protecting inverter substation - Google Patents

Abstract

FIELD: electrical engineering, c. Particularly, protection of invariant converter stations of power transmissions and direct current inserts against damages arising from the breaking of communications of one, part or all of the converters of these substations with receiving power systems of the alternating current connected to the substations through lines and communication switches. The aim of the invention is to increase the reliability of protection by increasing the speed and, as a result, preventing equipment damage. The goal is achieved by measuring the currents in the circuits of the valve windings of converter transformers 4, 5, 6 substations, b jHtptacacmeny (L oo 4: to ucmovHUMOH constant current F (l

Description

in the circuits of the network windings of the converter transformers 4, 5, 6; in the circuits of the lines 19, 20 and the switches 7-16. For each of the transducers .1, 2, 3, the fact of disconnection from the power system is determined by fixing the absence of current in the circuit of the network circuit of the converter transformer 4, 5 or 6 or -z of the circuit breakers 7-15 or 16 of the circuit. this converter with lines

one

The invention relates to electrical engineering, in particular, to the protection of inverter converter stations for power transmission :. and inserts of direct current from damages arising from the breaking of the connections of one part or all of the converters of these substations with alternating current receiving power systems connected to the substations through lines and communication switches.

The aim of the invention is to increase the reliability of protection of an inverter substation by increasing the speed of protection and, as a result, the prevention of equipment damage.

FIG. 1 is shown as an example. A circuit of an inverter substation protected by the proposed protection method, its communication elements with a receiving power system with placement in the circuit of current measuring sensors; in fig. 2 is a functional diagram of the device that implements the proposed method,

An inverter converter substation, comprising bridge inverter converters 1-3 (Fig. 1) and converter transformers 4-6, is connected to the power system through communication switches 7-16, connected between substation bus systems 17- and 18, and communication lines 19j 20. . The filter filters 21 are connected to the tertiary windings of the transformers 4-6, and the buses 17 and 18 through the switches 7-10 and 11 14, respectively, the filters 22 and 23 harmonics, In the circuit of the lines, switches, network and

9, .20s or in the circuits of all communication lines with simultaneous presence in these conditions of the current in the circuit of any of the valve coils of the converter transformer 4, 5 or 6, and then short-circuiting the DC sources that supply the inverter Ij disconnected from the power system 2, 3, and turn off these sources, - 2 Il.

The valve windings of the transformers include 24-44 current sensors, and parallel to the power supply transformers 1-3 current sources - shorting devices 5 45-47.

To the corresponding current sensors

. (DT) are connected (Fig. 2) threshold

current organs (TO) 48-55, to the outputs of which HE 560 61 inverters are connected. In addition, the device contains elements OR 62 and 63, elements AND 64 and 655, element OR 66, element And 67, and element 68 of memory,

Break The connection of any of the inverter converters, for example, converter 1, with the receiving power system is fixed, it is established that any of the currents is 1–55 40

the valve coils of the converter-0 transformer 4 of this converter, measured respectively by the current sensors 39, 40, under any of the following conditions.

A, There is no current of the network winding of the transformer 4, measured by the current sensor 36, which corresponds to the operation of the converter to the capacitor battery of filters 21,

connected to the tertiary winding - 30 transformer 4.

B. There are no currents in the circuit breakers of the converter 1 with the lines 19 and 20 of the communication measured by (sensors 24-27, with current

35, the mains winding of the transformer 4 may be maintained due to the operation of the converter, for example, to the load of the filter 22.

B. There are no currents Ij, IjjB lines x 19 and 20, measured by sensors

34s 35 current, while the converter operates on both filters 21 and filters 22, 23.

The conditions for the breakdown of communication between converter 1 and the power system, under conditions A, B, C, can be respectively written in the following form:

A (Aj5vfl.) / (Fl3,.; B (flj3vfl), 4A (fl2 (Vflj);

B (fl39Vfl4c) ()

where D is the logical signal j controlling the presence () or from 10

The cops OR 62 and 63 combine the signals D, Dzd, D respectively, the AND 64 element generates a signal of the signals Dg and the output signal of the OR element 62, the AND 65 element of the Dz 4I signals 35 The OR element 66 combines the signals the output signals of the AND elements 64, 65 , And element And 67 fixes the coincidence of the output signals of the elements OR 63 and 66 ,. those. generates a disconnection signal P. This signal triggers memory element 68, making () the corresponding 15 switching on of device 45, shorting the direct current source, feeding converter 1, and giving a signal to turn off this source.

Claims (1)

Invention Formula general current; V - a symbol of logical OR; L is the symbol of the logical I. The general condition of disconnection according to the described method for the inverter converter 1 20 R, (D59CH) L {D USDOD / Dz5) V DID24 D27Sh30 The protection circuit of the inverter converter station equipped with the breaking of the connection P.1) with the absence of 25 conversion transformers with valve and network windings and supplied from the DC sources with the breaking of its connection with the receiving power system connected to it through lines and switches This consists in measuring the currents in the circuits of the valve windings of the converter transformers and disconnecting the DC sources, characterized in that, in order to increase the protection reliability by Sheni speed and, consequently, preventing damage to the equipment, are measured the currents in the windings of network chains converter transformers in chains lines and switches communication -sv, for each of the transducers is fixed absence of current in one of said circuits simultaneously .If VII its P 0. After fixing the break in the connection of any of the transducers of the proposed method, the current source supplying the lost connection to the power system of the transducer is short-circuited using devices 45-47, in which both contact and non-contact elements can be used. The shortening of current sources can also be accomplished by forcing the valves to be turned on in one of the phases of the converter. After the source is short-circuited, it is disconnected, as in the known method. A device (4ig. 2) that implements the described method, for example, for converter 1, contains 35 connected 40 data to the corresponding sensors. the current is present in the circuit of any of the valve-threshold current organs 48-55, which form logic signals D about the presence or absence of the corresponding current. To the outputs of the latent organs 48-53, the HE 56-61 inverters are connected, which form the inverse signals. The power windings of the converter transformer, short-circuit the sources of direct current feeding the disconnectors disconnected from the receiving power system, and then disconnecting. The cops OR 62 and 63 combine the signals D, Dzd, D respectively, the AND 64 element generates a signal of the signals Dg and the output signal of the OR element 62, the AND 65 element of the Dz 4I signals 35 The OR element 66 combines the signals the output signals of the AND elements 64, 65 , And element And 67 fixes the coincidence of the output signals of the elements OR 63 and 66 ,. those. generates a disconnection signal P. By this signal, memory element 68 is activated, carried out 20 thirty 25 25 35 25 40  presence of current in the circuit of any of the windings of the converter transformer, short-circuit the sources of direct current supplying the converters disconnected from the receiving power system, and then disconnecting.