JPS63253859A - Controller for thyristor converter - Google Patents

Abstract

PURPOSE:To increase an operating efficiency, by a method wherein the title controller is provided with a first and a second counters and the trouble of a photoelectric transducing circuit is decided in accordance with the output numbers of both counters. CONSTITUTION:The controller of a thyristor transducer is constituted of a micro-computer 12, a first input circuit 13 for reading forward voltage signals 1a-Na, a second input circuit 14 for reading a gate pulse command (d), a RAM circuit 15, a ROM circuit 16, an output circuit 17 and a CPU circuit 18. Respective forward voltage signals 1a-Na are compared with forward voltage neglecting signals 1e-Ne from a micro-computer 11 in an AND circuit 19-1-N before inputting them into an OR circuit 17. By this operation, photoelectric transducing circuits 8-1-N neglect the existing forward voltage signals and preclude the inputting of the forward voltage signals into the OR circuit 9. As a result, a forward voltage OR signal (b) becomes zero and the gate pulse command (d) is stopped. Thereafter, various transducers may continue the operations thereof by the normal output of a photoelectric transducing circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a control and protection device for a thyristor converter used in DC power transmission and the like.

(Prior art) Conventionally, as a method of firing multiple thyristors connected in series or series-parallel with a narrow gate pulse, an AND of an energization command signal indicating the conduction period of a thyristor converter and the forward voltage of each thyristor is used. There is a method that issues a gate command when a condition is met.

The operating principle of a conventional thyristor converter control and protection device will be explained using FIG. A predetermined number of thyristors 1-1 to 1-N are connected in series, and a voltage dividing circuit 2 consisting of a resistor and a capacitor is connected in parallel. Further, forward voltage detection circuits 6-1 to 6-N each including a light emitting diode 3, a resistor 4, and a diode 5 connected in antiparallel to the light emitting diode are connected in parallel with each thyristor. The forward voltage signals i4 detected by the forward voltage detection circuits 6-1 to 6-N are transmitted to the photoelectric conversion circuits 8-1 to 8-8 by the light guides 7-1 to 7-N.
-N, the electrical signal M'ltl pressure signal 1a to Nn
The OR circuit 9 outputs a forward voltage OR signal.

Part of the energization command signal C indicating the conduction period of the thyristor converter and the forward voltage OR signal are matched in the AND circuit 10, and when the AND condition is met, the gate pulse command d is formed into a pulse by the pulse circuit 11. It is sent to a gate pulse generator, not shown. During normal operation, when a gate pulse is supplied to the thyristor, the thyristor fires and the forward voltage becomes 0, so the gate pulse command d is 1
It is one shot during the cycle. If the forward voltage OR signal does not become '0' with one gate pulse command 11, several gate pulse commands d are continuously sent out until it becomes '0'.

(Problems to be Solved by the Invention) In such a conventional control protection device, when one of the photoelectric conversion circuits for forward voltage signals, which has the same number as the thyristors, causes a failure in which the forward voltage signal continues to be present, the gate The pulse command will be emitted. A failure in which a gate pulse command is released is extremely dangerous for a thyristor converter, so the thyristor converter must be stopped and the failed part repaired. There was a problem in which the converter would stop if only one of them had a "forward voltage present" failure.

The present invention was developed in view of the shortcomings of the conventional control protection device, and when the gate pulse command is released due to a failure of the forward voltage FIT No. 1 river light conversion circuit, the thyristor converter is not stopped and can be operated normally. The purpose of the present invention is to provide a control and protection device for a thyristor converter that allows continued operation.

[Structure of the invention]

(Means for Solving the Problems) In order to realize a control protection device for such a thyristor converter, the present invention provides a gate pulse command d as shown in FIG.
It has a first counter implemented by a microcomputer 12 that counts the number of forward voltage signals 1a''Na generated, and a second counter implemented by the microcomputer 12 that counts the number of forward voltage signals 1a''Na. When the number exceeds a predetermined value and an abnormality occurs, the forward voltage signal 1a” detected at that time is determined by the output of the second counter.
The number of Na is compared with a predetermined number (for example, 2 or 3), and if it is less than the predetermined number, it is determined that there is a failure in the photoelectric conversion circuits 8-1 to 8-N, and the forward voltage signal detected at that time is Continue normal driving by ignoring.

(Function) Therefore, according to the present invention, when, for example, one or two of the photoelectric conversion circuits 8-1 to 8-N for forward voltage signals have a failure that continues to have a forward voltage signal present, , the gate pulse command d is released, and the output of the second counter becomes a predetermined number (for example, 4 or 5) or more. At this time, the number of forward voltage signals being detected is 1 or 2 in this example, which is smaller than a predetermined number (for example, 2 or 3), so this peculiar state of the forward voltage signal is ignored, and the forward voltage The signal should not be input to the input of the OR circuit 9. As a result, the forward voltage OR signal becomes "O" and the gate pulse command d is stopped. Thereafter, since the output of the failed photoelectric conversion circuit is ignored, the thyristor converter continues to operate with the output of the normal photoelectric conversion circuit.

(Example) One embodiment of the present invention will be described with reference to FIG.

In the figure, the same numbers and symbols as in FIG.

The microcomputer 12 has a first input circuit 13 for reading the forward voltage signal 1a''Na and a gate pulse command d.
A second input circuit 14 for reading data, a RAM circuit 15 for storing each signal data and calculation results, and a RAM circuit 15 for reading data, determining the number of abnormalities in the forward voltage signals 1a to Na, and determining the number of abnormalities and gate pulse commands. ROM that stores a protection logic function program for comparing numbers with predetermined numbers, etc.
It consists of a circuit 16, an output circuit 17 that outputs a signal 1e''Ne for ignoring a specific forward voltage signal when a predetermined condition is satisfied, and a CPU circuit 18 that controls each circuit of the microcomputer 12. Each of the six forward voltage signals 1a''Na is input to the microcomputer 11 by AND circuits 19-1 to 19-N before being input to the OR circuit 9.
It is matched with the forward voltage neglect signal 1e=Ne from .

This embodiment operates as follows. Forward voltage ignored signal 1e, which is the output of the microcomputer 11, is N.

is set to the "1" level as an initial value. It is assumed that a failure occurs in the photoelectric conversion circuit 8-1 in which the forward voltage signal continues to be present during operation of the thyristor converter. Since the forward voltage signal 1a remains at "1", the forward voltage OR signal 1a remains at "1", and the gate pulse command d continues to be output and released. The number of gate pulse commands d generated is counted by the CPU 1g and compared with the allowable number of gate pulse commands stored in the ROM circuit 16 in advance. In this case, the gate pulse command d is released, and the number of gate pulse commands is larger than the number of gate pulse commands during normal operation.Forward voltage signal 1 stored in the RAM circuit 15
By processing a=Na, the number of forward voltage signals at that time is determined. Compare the minimum number of forward voltage signals (for example, 2 or 3) stored in the ROM circuit 16 in advance with the number of forward voltage signals at this time (1 in this case), and if the number of forward voltage signals is smaller, the number of forward voltage signals that exist at that time is compared. A forward voltage disregard signal (le in this case) corresponding to the forward voltage signal is transmitted from the output circuit 17 to the AND circuit 19-1 as a level "0" signal. Since the le signal of one of the two outputs of the AND circuit 19-1 is at the rOJ level, this output is always rOJ, so the faulty forward voltage signal 1a is ignored and is not substantially input to the OR circuit 9. The thyristor converter is normally operated by the remaining forward voltage signal 2a=Na.

In the unlikely event that the forward voltage of the thyristor does not disappear even if a gate pulse is supplied due to an abnormality in the main circuit, etc., the number of forward voltage signals that exist at this time is greater than the minimum number of forward voltage signals, so the forward voltage The ignore signal is not sent. In this case, the gate pulse command is not sent, and an abnormality is detected by a gate pulse number abnormality detection circuit (not shown), and the thyristor converter is stopped.

As explained above, according to the present invention, a failure occurs in one or two of the forward voltage signal transformer circuits.

If the gate pulse command is suddenly released or released, normal operation can be continued by ignoring only the faulty forward voltage signal.

In the embodiment described above, it is better to use the duration of the forward voltage OR signal in FIG. 1 to count the number of gate pulse commands as a means of detecting an abnormality in the photoelectric conversion circuit for forward voltage signals. You can also. In this case, the forward voltage OR signal may be input to the second input circuit 14 of the microcomputer 12.

As another example, as shown in FIG. 3, a blip flow is generated by ANDing the energization command signal C and the forward voltage OR signal.
In the control protection circuit that sets the knob 20 to send out the gate pulse command d, and stops the gate pulse command by resetting this flip-flop 20 with the inverted signal f of the forward voltage OR signal, the gate pulse command d is The input to the computer 12 is the same as in the first embodiment, but the duration of the gate pulse command d may be monitored as a means of abnormality detection.

〔Effect of the invention〕

As explained above, according to the present invention, when a very small number of the many photoelectric conversion circuits for forward voltage signals fail and the gate pulse command is not issued, this failure situation is determined. , normal operation can be continued without stopping the thyristor converter. This eliminates the need to stop the thyristor converter due to a very small number of failures in the photoelectric conversion circuit, which has a large number of circuits and components and has a relatively high failure rate, so that the operating rate of the thyristor converter can be greatly increased.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram showing a conventional embodiment, and FIG. 3 is a block diagram showing another embodiment of the present invention. 1... Thyristor, 6... Forward voltage detection circuit. DESCRIPTION OF SYMBOLS 10... AND circuit, 12... Microcomputer, 13... First input circuit, 14... Second input circuit, 15... RAM circuit, 16
...ROM circuit, 17...output circuit,
18... CPU circuit, C... communication ti command signal,
e...Forward voltage ignored signal. Agent Patent Attorney Noriyuki Chika Ken Yudo Daishimaru Ken Figure 1

Claims (1)

[Claims] A thyristor converter comprising a plurality of thyristors connected in series or series-parallel, and a plurality of forward voltage detection means for detecting the forward voltage applied to the thyristors, with the AND condition of the output signal of the forward voltage detection means and the energization command signal. A control device for a thyristor converter that supplies a gate signal to the thyristor, comprising a first counting means for counting the number of occurrences of the gate signal, and a second counting means for counting the output signal of the forward voltage detection means. When the output of the first counting means exceeds a predetermined number, the output of the second counting means is compared with the predetermined number, and if the output is less than the predetermined number, the forward voltage detected at that time is A control device for a thyristor converter, characterized in that the output signal of the means is ignored.