JPH0222628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gate drive device for a high voltage thyristor converter that requires high reliability in DC power transmission equipment and the like.

High-voltage thyristor converters used for DC power transmission, etc. are composed of multiple thyristors connected in series or in series-parallel, and each thyristor receives gate pulses transmitted by a gate pulse generator installed at ground potential. It is then ignited. The gate pulse generator uses a voltage signal obtained by detecting a forward voltage applied to a plurality of thyristors (hereinafter referred to as valves) connected in series in order to control and transmit an optimal gate pulse to the thyristors (hereinafter referred to as valves).

FIG. 1 is a block diagram of a conventional gate pulse generator for a high voltage thyristor converter. The operation until the gate pulse is transmitted to each thyristor will be described below. pulse generator
The PG inputs a control signal a that determines the firing phase and conduction period of the valve from a control and protection device (not shown here) that controls and protects the entire conversion device. Also the light-triggered thyristor of the valve VL
Voltage detection circuit connected in parallel to T ₁ , T ₂ , T ₃
VD ₁ , VD ₂ , VD ₃ are optically triggered thyristors T ₁ ,
The forward voltage applied to T ₂ and T ₃ is detected. This forward voltage is converted into an optical signal by the voltage detection circuit VD, and transmitted to the photoelectric converter LEC installed at ground potential by the light guide LG, which transmits light.
Here, it is converted into an electric signal again and is based on one voltage signal b using majority logic or the like. The pulse generator PG determines the timing to generate a narrow gate pulse to the optical trigger thyristor by ANDing the control signal a that determines the firing phase and conduction period and the voltage signal b corresponding to the forward voltage, and generates a predetermined pulse. Send the gate signal c of width to the amplifier AMP. The amplifier AMP is a light emitting diode during the gate signal c.
A current is passed through L ₁ , L ₂ , etc. to convert the electrical signal into an optical gate signal. Optical gate signal is light guide
LG serves as a gate input for each trigger thyristor T ₁ , T ₂ , . . . and turns on, making the valve VL conductive. BTW pulse generator PG or amplifier
Due to a failure of the AMP or even the photoelectric converter LEC, the light emitting diodes L ₁ , L ₂ ... may not be able to generate a light gate signal, or the light gate signal may not be output properly, making it impossible to control the bulb normally. In addition, there is a possibility that the optical trigger thyristor may be damaged. In the case of such an abnormality, it is impossible to operate the thyristor converter normally, so it is necessary to disconnect the thyristor converter from the system and stop it for protection.

As mentioned above, with conventional gate pulse generators, it is impossible to detect and protect against abnormalities in the pulse generator PG, amplifier AMP, photoelectric converter LEC, etc., and the thyristor converter continues to operate. It is also impossible to do so.

Thyristor converters for DC power transmission are required to have particularly high reliability due to their use, and stoppages due to accidents must be avoided as much as possible. Gate pulse generators generally have lower reliability than thyristor valves because they use more electrical parts, and when a gate pulse generator breaks down, it can only be restarted after it has been stopped and the faulty part has been repaired. There is a drawback.

The present invention focuses on the conventional drawback that when the gate pulse generator fails, the thyristor converter is stopped and the system is also stopped. It is an object of the present invention to provide a highly reliable gate drive device for a high voltage thyristor converter that can continue operation without stopping the converter or the entire converter.

The present invention will be explained below using FIG. 2. FIG. 2 is a block diagram of a gate pulse generator for a high voltage thyristor converter according to the present invention. Components with the same functions or signals as those in FIG. 1 are denoted by the same symbols, so a description thereof will be omitted. The difference from Fig. 1 is that there are three gate pulse generator systems, A, A, and A, respectively.
The gate pulse generators of the B and C systems independently transmit gate pulses to the valve VL. The operation will be explained below. Control signals a-A, a- each independently issued from a control protection device (not shown)
B, a-C is pulse generator PG of A, B, C system
-A, PG-B, and PG-C are respectively input. In the following, the A system will be representatively explained.

The A-system pulse generator PG-A which receives the control signal a-A generates a narrow gate signal c-A to the amplifier AMP-A. The output of amplifier AMP-A is
Light guide
It is transmitted via LG to the gates of optical trigger thyristors T1~Tn. Similarly, the light emitting diodes L _1B to L _1C of the B and C systems also transmit optical gate signals to the gates of the optical trigger thyristors T ₁ to Tn, respectively.
Optical trigger thyristors T ₁ to Tn should be equipped with three light gates, or use a three-branch light guide, or condense the light from the light guide from each system with a lens, etc. It is possible to turn on the optical gate signal from any system by transmitting it to the gate of the optical trigger thyristor. The voltage detection circuit VD is divided into the same number of groups as the number of pulse generators PG (three groups in the illustrated example), and each group outputs at least three (three in the illustrated example) photoelectric converters LEC, which will be described later. I try to give it to

Photoelectric converters are LEC-A, LEC-B, LEC-C
The input from the voltage detection circuit VD of each group is made into one signal by majority logic etc. and is fed back to the corresponding pulse generators PG-A, PG-B, PG-C, and a voltage signal b-A, Generate b-B and b-C. Here, photoelectric converters LEC-A, LEC-B,
LEC-C to pulse generator PG-A, PG-B, PG
-C and the same number of pulse generators PG-A,
This is due to the multiple system configuration of PG-B and PG-C. In other words, if the optical converter is one LEC-A and is common to each system regardless of the multiple system configuration of the pulse generator, then this common optical converter LEC-A
This is because if a failure occurs, the entire system becomes abnormal and the multi-system configuration becomes meaningless.

The timing of gate pulse generation is determined by the voltage signal b-A of the A system and the control signal a-A, and the gate signal c-A is generated. In addition, in order to detect continuity of the light emitting diode, a light emitting diode for continuity detection is connected in series with the light emitting diode for generating an optical gate signal.
The optical gate signal is detected by connecting L _SA (L _SB for B system and L _SC for C system) and detecting the optical signal. This continuity detection signal is sent to the failure determination circuit FD, which creates a normal continuity detection signal from the continuity detection signals of each system using majority logic, etc., and compares it with each continuity detection signal to generate an abnormal optical gate signal. generator can be detected. When an abnormality is detected, switches S-A, S-B, and S-C are short-circuited using semiconductor switching elements connected in parallel to the light-emitting diode, thereby bypassing the light-emitting diode current to switch S and switching on the light gate. It is possible to stop the signal.

The above is the multi-system configuration of the gate pulse generator of the present invention. Continuity of the light emitting diode can be detected by directly detecting the current flowing through the light emitting diode using CT, or by detecting the voltage drop of the light emitting diode. I can do it even if I wear it. Furthermore, when a switch S is connected in series with the light emitting diode and an abnormality is detected, the switch S may be opened to stop the optical gate signal. Note that the failure determination circuit FD sends a failure signal d indicating an abnormal gate pulse generator to the control protection device to notify it of the abnormality.

According to the present invention, since the voltage signal is divided into three parts, even if the gate pulse generator of the A system fails, the failure determination circuit FD can detect the abnormality of the A system, and the gate pulse can be locked by the switch S-A. Therefore, while operating on B and C systems, A
It is possible to separate the system's gate pulse generator from the valve. Note that the B and C systems are not affected in any way when the A system is abnormal.

As described above, according to the present invention, even if system A becomes abnormal, the operation of the thyristor converter can be continued through systems B and C, so there is no need to stop the system, which only improves reliability. A is broken and disconnected even when the valve is in operation, where a gate pulse is supplied to the valve to drive the valve, or during floating, which is a gate block state when voltage is applied to the valve, or even in the so-called standby state.
Repair the faulty part of the gate pulse generator of the grid,
It can again be connected to the bulb to generate a light gating signal. Therefore, it is particularly suitable for gate systems of thyristor converters that require high reliability, such as in DC power transmission. In the above explanation, the thyristor in the bulb is explained as a light-triggered thyristor, but if an electrically triggered thyristor is used, the same effect can be achieved by converting the light gate signal into an electric gate signal at each thyristor potential section. can be obtained. Furthermore, gate pulse generators A, B,
Although the explanation is based on the three systems in C, similar effects can be obtained if multiple systems are used. It goes without saying that the voltage signal is also divided according to the multiplexed system.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional gate driving device for a high voltage thyristor converter, and FIG. 2 is a block diagram of a gate driving device for a high voltage thyristor converter according to the present invention. PG...Pulse generator, AMP...Amplifier, VL
...Valve, T1~Tn...Light trigger thyristor,
VD1-VDn...Voltage detection circuit, LEC...Photoelectric converter, FD...Failure determination circuit, L1-Ln...Light-emitting diode, L _S ...Light-emitting diode for detection, S...
Switch, LG...Light guide.

Claims (1)

[Claims] 1. In a gate drive device for a high voltage thyristor converter consisting of a plurality of thyristors connected in series or in parallel, an independent control signal is provided that determines the firing phase and conduction period for driving the thyristors. at least three sets of pulse generators, a plurality of voltage detection means for detecting forward voltages applied to the thyristors, and voltage detection means provided in the same number as the pulse generators and divided into the same number of groups as the pulse generators. a signal feedback means having at least three photoelectric converters to which the output of the means is given for each group and giving the output signal of each photoelectric converter to the corresponding pulse generator as one signal by majority logic; and corresponding to the plurality of thyristors. The output from the pulse generator is applied to each set of light emitting elements and converted into an optical gate signal, and the light gate signal is applied from each set of light emitting elements to the gate of each thyristor. a generating means, and a failure monitoring means that inputs the outputs of the light emitting elements of each set and determines a faulty pulse generator, disconnects the system of the faulty pulse generator, and continues driving the thyristor with another healthy pulse generator. A gate drive device for a high voltage thyristor converter, characterized by comprising: