JPS63217918A - Direct current relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a DC current relay device for protecting DC circuits such as feeder circuits of DC electric railways.

[Conventional technology]

Figure 4 is a block connection diagram showing the principle of a conventional DC protective relay device, as shown in Figure 10, page 26, IEEJ Technical Report (Part I) No. 83, 1960, published by the Institute of Electrical Engineers of Japan. In the figure, 1 is a DC circuit such as a DC feeder line,
2 is an unsaturated current transformer, 3 is an integrating circuit connected to the secondary circuit of the unsaturated current transformer 2, and 4 is a signal processing circuit connected to the output side of the integrating circuit 3.

Next, the operation will be explained. When a current flows through the DC circuit 1 passed through the unsaturated current transformer 2, a differential value of the current flowing through the DC circuit 1 is output to the secondary side of the unsaturated current transformer 2, and a change in the current is extracted.

The current differentiated by the current transformer 2 is input to an integrating circuit 3 having a time constant considerably larger than that of the current transformer 2, where it is integrated and is similar to the change in the current flowing through the DC circuit 1. This signal with a similar waveform is input to the signal processing circuit 4, and if it becomes larger than a set level, it is determined that there is an accident in the DC feeder line.

By the way, in the case of a short-circuit accident on the DC feeder line of a DC electric railway, not only is the fault current detected in a small current range that cannot be detected and cut off by a high-speed breaker, but also the load current such as train operating current is detected. A DC current relay device that does not operate unnecessarily but reliably detects fault current is required.

In addition, it is desirable to keep the setting value of a DC current relay device as low as possible within a range that does not cause unnecessary operation by the load. It is necessary to detect fault current in the area.

[Problem that the invention seeks to solve]

Since the conventional DC current relay device is configured as one or more, the current flowing in the DC circuit is differentiated using an unsaturated current transformer with a holding structure, and a similar waveform is created using an integrating circuit 3. The signal needed to be processed.

Therefore, the signal processing circuit 4 cannot utilize the current flowing through the DC circuit 1 itself, and therefore cannot detect the fault current quickly and at high speed, which imposes restrictions on improving protection performance, and also prevents unsaturated Current transformer 2 and integrating circuit 3
This has led to problems such as the equipment being expensive.

The present invention has been made to solve the above-mentioned problems, and aims to provide a DC current relay device that can improve detection sensitivity and lower the setting value than before.

[Means for solving problems]

The DC current relay device according to the present invention includes a storage device that stores a processing program for a DC circuit current input into an input device, and monitors the time required for the DC current to reach the next current level from a certain current level. However, if the arrival time becomes smaller than a set value, the device is equipped with a signal processing device that determines that an accident has occurred and outputs a command to open the DC breaker.

[Effect]

The signal processing device according to the present invention determines that an accident has occurred and issues a command to open the DC breaker when the time required for the DC current taken in from the DC circuit to reach the next current level from a certain current level is less than or equal to a set value. By operating to output the fault current, it is possible to detect the fault current quickly and reliably, and to remove the fault current at an early stage.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 21 is a DC circuit such as a DC feeder line, 22
23 is a current transformer that converts the current flowing through the DC circuit 21 into an input signal to a processing device in order to input it to the microprocessor described below; 23 is an input device for inputting the input signal to the microprocessor described later; 24 is a A microprocessor (central processing unit) is used as a signal processing device, and this microprocessor 24 determines the occurrence of an accident by monitoring the time it takes for the above current to reach the next current level, and interrupts the DC current. Outputs a command to open the device. 25 is a storage device that stores a processing program for processing control program data for controlling this device; 26 is an output device that outputs an opening control signal to the DC breaker 20 based on an opening command from the microprocessor 24;

Figure 2 is a characteristic diagram used to explain the following operations. This characteristic diagram shows the DC current of feeder lines of DC railway substations, etc. on coordinates with current value on the vertical axis and time on the horizontal axis. It shows the current in the circuit over time, Il*l1ll...
...IJ, Iy+t are current levels. Here, 3
1 is the operating current of the chopper control train, 32 is the operating current of the cam control train, and 33 is the fault current.

The microprocessor 24 determines the time required for the current taken in from the DC circuit 21 to reach the next current level from a certain current level to IiI! If the arrival time is less than a set value, it is determined that an accident has occurred, and the operating current and fault current are distinguished. In other words, while operating current takes a long time to reach the next current level from one current level, fault current can be identified because it takes a short time to reach the next current level.

Next, the operation will be explained according to the flowchart shown in FIG.

First, initialize the entire system in step 5T5.
0), from the next current level Ij to the next current level I
In order to calculate the time required to reach l+1, the DC current i (t) is read as an actual measurement value via the current transformer 22 at -regular intervals (step 5T51).

Note that this arrival time is determined when the current 1(t) is greater than 0 (i
(t)>O) is determined (step 5T52), and if it is large, it is determined whether the current i (t) exceeds the current level j (step 5T54).

If it does, it is determined whether the current 1(t) exceeds the current level E,+, step 5T55), and if it does not, the current 1(t) is between a certain current level Ij and the next current level E1 or 1. It can be determined that it exists in - the current 1(t) before the period also has a certain current level Ij and the next current level I
Step 5T56)
, if so, the timer T is counted up (step 5T57).

After repeating the above steps, if the current 1(t) has become larger than the next current level E,+, step 5T5
If the determination is 5, since the time taken to reach the next current level +1 from a certain current level Ej is counted by the timer T, it is determined whether the timer T exceeds the set value (step 5T60). If it exceeds the limit, it is determined that it is an accident and a command to open the DC breaker is issued (Step 5T63), Step 5
After initial setting is performed at T50, the processing from step ST51 onwards is repeated. If the current level is not exceeded, increase the current level by one, so that U = , i + 1 (step 5T61),
After resetting timer T (step 5T62).

Step 5The processing from T51 onwards is repeated.

Note that although the above embodiment uses a microprocessor, a signal processing device capable of digital processing or analog processing may be used, and the same effect as that of the color measurement described above can be obtained.

In addition, in the above embodiment, in order to distinguish between fault current and operating current, a case was explained in which the arrival time from one current level to the next current level is detected. It is also possible to use it as a resistance ground fault detection device.

In addition, in the above embodiment, each determination (step 5T
52, 5T54, 5T55, 5T56゜5T60) is 1
High reliability can be achieved by providing redundancy for determining whether or not the condition has been satisfied only once, but several times or several times in succession. Reliability can be further improved if the condition for outputting the DC breaker open command is that the arrival time exceeds the set value at several levels.

〔Effect of the invention〕

As described above, according to the present invention, the time taken for the DC current taken in from the DC circuit to reach the next current level from a certain current level is determined, and it is determined whether or not this arrival time exceeds a set value. If the current exceeds , it is determined that a fault current is flowing, and a command to open the DC breaker is issued.In this way, the discharge current can be detected quickly and reliably, and the fault current can be removed at an early stage. Another advantage is that the setting value can be lowered than before.

[Brief explanation of the drawing]

Fig. 1 is a block connection diagram showing a DC current relay bag according to an embodiment of the present invention, Fig. 2 is a characteristic diagram explaining the operation of the DC current relay device, and Fig. 3 is a flowchart explaining the operation. FIG. 4 is a block connection diagram of a conventional DC current relay device. 20 is a DC breaker, 23 is an input device, 24 is a signal processing device (microprocessor), 25 is a storage device, and 26 is an output device. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Patent applicant: Mitsubishi Electric Corporation No. 1 Figure 21: Direct emotion circuit Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] an input device that takes in a DC current of a DC circuit; a storage device that stores a processing program for the DC current that is taken into the input device; and a storage device that monitors the time taken for the DC current to reach the next current level from a certain current level. a signal processing device that outputs a command to open a DC breaker that determines that an accident has occurred and cuts off the DC circuit when the arrival time becomes smaller than a set value; and a signal processing device that outputs a command to open the DC breaker to cut off the DC circuit; and a signal processing device that controls the DC breaker to open based on the release command. A direct current relay device comprising an output device that outputs a signal.