JPH1084643A - Open current detector for current breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to provide a more compact circuit breaker and to constitute the circuit with stationary parts such as an integrated circuit, by providing coils respectively for taking out the differentiated value of an open current of the circuit breaker during the operation for each protection relay for overcurrent detection and short-circuit detection, and by triggering the differentiated value at the initial stage of current rise. SOLUTION: In each protection relay, an open current of a circuit breaker during operation is applied through a coil 21 and taken out by triggering an initial differential voltage of rising, its minus region is removed by a rectifier circuit 22 and then input to a comparator 25 through an amplifier 23. Then, the presence or absence of open current is judged by a comparator 25, the time width of the output voltage waveform of the comparator 25 is extended by a timer 26 and is transmitted to a remote monitor controller through an optical relay 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for subdividing fault condition monitoring in electric power equipment, so that the fault condition can be grasped more specifically than before.

[0002]

[Prior art]

1) The power equipment referred to here refers to comprehensive equipment including a plurality of power systems (for example, Shinanogawa power system, Tadamigawa power system, etc.). A power system is a system that responds to power demand from power sources (hydro, thermal, nuclear power plants, etc.), through power transport facilities (substations, transmission lines, distribution lines), and loads (eg, cities, factories, electric railways). ) Is a generic term for equipment in which all elements are organically closely linked and are involved from the generation to consumption of electric power. The power system has communication equipment, remote monitoring equipment, automatic control equipment, and the like corresponding to the neural system. The transmission system that connects the power plant and the load with a high-voltage transmission line is generally constructed in a radial system. As the scale of the system increases, the system may be linked to another adjacent power system at the receiving end or at an intermediate point in order to improve the transmission stability and reliability. In order to operate and manage these systems rationally, it is necessary to grasp the status of each system in a wide area in real time and take appropriate measures as essential requirements. An organization that centrally manages these many facilities is generally called a control center. The control station may be provided on the power transmission end side, the power reception end side, or any intermediate position therebetween. The control station has a monitoring panel for displaying the status of the power system under its jurisdiction. The monitoring panel displays the status of the electric power system under its control, and the status is displayed on the system diagram panel or the instrument panel itself, or a part of the function is displayed on the CRT screen under computer control. Display generators, transformers, switchgear, etc. in the form of images. When these power systems are viewed from the viewpoint of the communication equipment system, there is a communication slave station for each equipment to be monitored at the site, and the control station has a communication master station dedicated to the power system to which the communication slave station belongs. 2) FIG. 2 shows the original form of the means for transmitting the display of the switchboard placed on the site power equipment to the remote monitoring control device placed at the control center, that is, the conventional means. In the figure, 1R is an R-phase overcurrent protection relay, 2T is a T-phase overcurrent protection relay, 3R
Is an R-phase short-circuit detection protection relay, 4T is a T-phase short-circuit detection protection relay, 5 is an integrated relay for overcurrent detection and an operation residual indicator,
5a is a contact that stores the operation of overcurrent detection and is continuously conductive, 6 is an integrated relay and short-circuit detection residual operation indicator, 6a
Is a contact that stores the operation of short-circuit detection and is continuously conductive; 7 is an integrated relay for overcurrent and short-circuit detection; 9 is a bell alarm circuit, 10 is a solenoid for opening a circuit breaker, and 11 is a contact which conducts when the circuit breaker is closed.

In the method shown in FIG. 2, the protection relays 1R, 2T, 3
Since the operating currents of R and 4T are all collected in the centralized relay 7 and flow, and only the status indication of the flow is sent as the display input of the remote monitoring control device 28, the displayed failure phenomenon of the power equipment is excessive. By load (protection relay 1
R, 2T) or a short-circuit (operation of the protective relays 3R, 4T) without being subdivided, and is transmitted to the control station in charge of the operation. The control station was inconvenient because the actual situation of the failure could not be grasped.

[0004] By improving the method of FIG. 2, at least one two-winding display relay is provided for each protection relay so that the state of each of the protection relays 1R, 2T, 3R, and 4T can be separately transmitted. FIG. 3 shows a configuration performed on a conventional extension line.
Circuit. In FIG. 3 showing this, 32R, 32
a is an R-phase overcurrent display two-winding relay and a contact, 33T, 3
3a is a T-phase overcurrent display two-winding relay and a contact, 34R,
34a is a two-winding relay and a contact for R-phase short-circuit indication, and 3
5T and 35a are two-winding relays for T-phase short-circuit display and contacts.

The details of the two-winding relay commonly used in the above two circuits are described in, for example, FIG.
And a two-winding relay provided with at least two contacts. In FIG. 4, 7A is a primary (pickup) coil of 0.14Ω, and 7B is a secondary (hold) coil of 2,000.
Ω, 19 is a secondary coil short-circuit contact, and 20 is a remote control display a contact. However, the operation time is about 10 ms,
The recovery time is about 150 ms.

3) The operation of the above circuit will be described.
When any one of the protection relays 1R, 2T, 3R, 4T operates, an open current is supplied to the open solenoid 10 of the circuit breaker. The operation of the detected protection relay is restored. In addition, the remote monitoring control device 28 or 8 that transmits the operation state of the protection relay to the control station, in order to cope with simultaneous competition communication with other electric stations, sets the input signal time from the switchboard protection device to 100 ms or more. It is stipulated to continue for a certain period of time. Therefore, the function of the open current detector 7 is about 60 ms.
Open current is detected within the time of
Conduction is required to be continued for the above-mentioned fixed time.

4) Primary (pickup) of two-winding relay
The coil 7A has a low resistance of about 0.14Ω, and has a current capacity for allowing a current of the tripping solenoid 10 of the circuit breaker for interrupting the fault power. The detection time is about 10 ms. The secondary (hold) coil 7B is a coil having a large number of turns. If the secondary coil is short-circuited to the circuit by operating contacts 19, the primary coil current is lost by opening the circuit breaker. When the two-winding relay returns, the magnetism of the common iron core is slowly reduced.
The conduction time of 0 is extended to about 150 ms.

5) A method of linking a Hall element with a magnetic flux of an open current is generally used for detecting a direct current. FIG. 5 shows a circuit for detecting an open current by a Hall element.
If the open current is detected by the C-shaped iron core 40 and the Hall element 40-1 in each of the protection relays 1R, 2T, 3R, and 4T, and the output time is extended, the operation display of the protection relay can be segmented. . In the figure, 40 is a C-shaped iron core, 40
-1 is a Hall element inserted in the gap of the C-shaped iron core 40, 41 is an R-phase overcurrent operation Hall detector, 41a is a detection output contact (power MOS contact), 42 is a T-phase overcurrent operation Hall detector, 42a is a detection output contact, 43 is an R-phase short-circuit operation hole detector, 43a is a detection output contact, 44 is a T-phase short-circuit operation hole detector, 44a is a detection output contact, 16,
41 to 44 are common power supply circuits.

[0009]

[Problems to be solved by the invention]

1) The improvement of the existing switchboard using the two-winding relay shown in FIG. 3 has the following disadvantages. 1. When the size of the relay is large, a case for storing the relay is required to protect the contact mechanism, and the space occupied by the relay is large, making it difficult to improve the existing switchboard. Roughly, the dimensions are 130 mm in height, 80 mm in width and 132 mm in depth. Four circuits are stored and 235 mm in length and 168 in width.
mm and a depth of about 179 mm. 2. I want to abolish the use of relays with moving parts and make them stationary. 3. Two-winding relays are difficult to obtain because they are special relays. Moreover, there is a possibility that production will be discontinued in the future.

2) The improvement of the existing switchboard using the Hall element has the following disadvantages. 1. In order to use a Hall element and detect an open current while avoiding an interrupt in an open circuit, 40-1 Hall elements must be used.
0 is inserted into the air gap of the magnetic circuit of the C-shaped iron core to extract and detect the strength of the magnetic field due to the open current. Many components such as a C-type iron core, an amplifier circuit, a constant current circuit, and the like are required. 2. The open circuit current detected by the Hall element needs to be lowered in the determination level of a determiner for extracting as a trigger a waveform having a small change rate (similar to the open current) as shown by a waveform 31 shown in the upper left of FIG. Malfunction due to voltage is likely to occur. 3. Even if the opening current is detected by the Hall element, a timer circuit for extending and outputting the time width of the opening current is required.

[0011]

[Means for Solving the Problems]

1) For each protection relay 1R, 2T, 3R, 4T, a coil 2 for taking out the differential value of the open circuit current of the circuit breaker during its operation
1 are provided (see FIG. 1). Then, an open current is passed through each coil to take out each of them. 2) Normally, since the breaker opening solenoid 10 has a large inductance and is within a constant resistance value, the differential value of the opening current at the beginning of the rise is the second waveform 32 in the upper left of FIG.
Focusing on a large change in a certain direction as shown in (1), means for triggering the differential value at the beginning of rising as a trigger were configured as follows.

3) The voltage of the waveform 32 induced in the coil is used by the rectifier circuit 22 composed of a rectifier and an operational amplifier or the like to determine only the differential value of the opening current in the initial rising of the positive direction. 4) Operational amplifier 2 for amplifying to the voltage level required for determination
3 were provided. 5) The reference voltage is applied to the decision unit 25, and And d. Is inputted, and the presence or absence of the open current is compared and determined. The reference voltage is a variable resistor 24 (VR in FIG. 8).
1 to VR4), it is possible to cope with the inherent value of the open current of the circuit breaker used. 6) A timer circuit 2 for processing into a DC voltage that continues for a certain period of time, triggered by an output indicating that there is an open current by the determiner.
6 operates to ensure a constant conduction time required for the remote monitoring and control device 8. By selecting the time constant of the timer circuit, the conduction time required for the remote monitoring control device 8 can be arbitrarily designed.

7) By supplying the output of the timer circuit 26 to the light emitting diode, the MOS optical relay 27 (to be described in detail later) is operated, and a voltage signal insulated from the power supply of this device is converted to a remote monitoring control device 8 To communicate. 8) When an integrated circuit component is used as a component, the volume can be reduced by housing four circuits including the power supply portion in one housing (see FIG. 8). 9) All circuit components can be replaced with static ones. 10) Provide a filter in the power supply circuit to avoid malfunction. 11) A variable resistor 24 (V in FIG. 8) for creating a reference voltage for judgment
R1 to VR4) are arranged so as to be adjustable outside the housing.

When four circuits are stored according to the present invention,
26mm, width 230mm, depth 40mm, volume 1159.2
subsided to cm ^3. However, if four circuits are accommodated by the conventional technology, at least 235 mm in length, 168 mm in width, and 179 mm in depth
The volume became 7066.9 cm ³ . Therefore, according to the present invention, the volume ratio can be reduced to about 1/6.

[0015]

FIG. 6 is a circuit diagram of the circuit of the present invention shown in FIG. 1, for example, a detection coil 21 connected in series to an R-phase overcurrent protection relay 1R, an R-phase overcurrent operation detector 12 receiving the output of the coil, FIG. 3 is a diagram illustrating a detailed circuit configuration of a detection output contact 12a and the like for displaying an operation state of the detector, with an electric waveform of a main part of the circuit added. In FIG. 6, reference numeral 21 denotes a coil for extracting a differential value of the open current, 22 a circuit for rectifying a voltage induced in the coil to generate a voltage necessary for determining the current direction, and 23 amplifying to a voltage level required for the determination. An operational amplifier (amplification degree can be changed by the ratio of R2 and R3), 24 is a variable resistor for adjusting the reference voltage of the comparator to a differential value of the local open current, 25 is a comparator for determining the presence or absence of the open current, 26 is a timer for extending the time width of the output voltage of the comparator, 27 is an optical relay for transmitting the output of the timer to the remote monitoring control device 8, and 28 is a power supply circuit.

The waveform of the open circuit current of the circuit breaker when the protection relay operates is approximated to the waveform 31 by the circuit constant of the circuit breaker opening solenoid 10. This open current is passed through the coil 21 and is detected by means for taking out the differential voltage at the initial rise as a trigger. The output differential voltage of the coil 21 is a waveform 32. After the minus region of 32 is removed by the rectifier circuit 22, the waveform passes through the amplifier 23 and becomes the comparison input of the comparator 25.

The comparator 25 determines whether there is an open current. The waveform 34 is the output voltage of the comparator 25, and the waveform 35 is the output voltage of the current detector, the time width of which is extended by the timer 26. The operation time from the rise of the open current to the waveform 35 is 2 ms, and the time width of the waveform 35 is 112 ms, which satisfies the operation time duty of the function of the current detector. Reference numeral 27 denotes an embodiment of an optical relay, which uses an output optical relay (optical relay) with low power consumption to transmit the output extended by the timer to the remote monitoring control device 8. When light is received, the MOS transistor conducts, and when there is no light, the MOS transistor is turned off. When the optical relay 27 is used, it can be opened and closed with a weak current, can transmit a signal while isolating the primary side and the secondary side, there is no contact chattering (vibration) that is likely to occur in the electromagnetic relay, and it is easy to open and close the weak current. It has features such as.

In FIG. 7, reference numeral 31 denotes a waveform of the open current (the maximum value is 4.6 A). Reference numeral 32 denotes a differential voltage (maximum value: 1.4 V) of the open current generated in the through coil 21. Reference numeral 33 denotes the rectified and amplified output voltage of the amplifier 23 (maximum value: 2.8 V, amplification factor = 2). Reference numeral 34 denotes an output voltage (maximum value 5V) of the comparator 25. Reference numeral 35 denotes the output voltage of the optical relay 27 (maximum value 108 V).

FIG. 8 shows three external views of an embodiment of the apparatus of the present invention. FIG. 8A is a plan view of an apparatus in which four circuits of each phase shown in FIG. 6 are collectively housed in one case. FIG. 8B is a front view, and FIG. 8C is a side view.
For example, in FIG. 6, the open current of the protection relay 1R passes through the detection coil 21 and the differential value of the current is transmitted to the terminal 1K.
And 1L. This terminal 1K,
1L corresponds to the right end terminals 1K and 1L of the IN terminal block on the upper left side in FIG. 8A. The result of detecting the open current of the protection relay 1R is shown by the terminals COM and OU on the lower right side in FIG.
Output from T. These terminals correspond to the terminal COM (common) and OUT1 on the OUT terminal block on the right side of FIG. 8A. Terminals P and N indicated as 100 V DC at the right end of FIG. 6 supply common power to the four built-in circuits, which correspond to terminals + and − in FIG. 8A, respectively. The circle denoted by reference numeral 24 is the variable resistor for adjusting the reference voltage shown in FIG. 6, and VR1 to VR4 are assigned to each of the four built-in circuits. The approximate dimensions of the embodiment device illustrated in FIG.
It is as compact as about 25 cm, height: 10 cm and depth: about 4 cm, which greatly contributes to space saving. This device is used, for example, by installing it in a power distribution board and / or a power distribution board of an electric railway substation.

[0020]

【The invention's effect】

1) When the current detector according to the present invention is used, since there is no interruption of the coil or the like in the open circuit, the occurrence of a dangerous state in which the circuit breaker cannot be opened at the time of failure of the power equipment accompanying the improvement work is suppressed. 2) Comparing the four-circuit housing of the present invention with the conventional four-circuit housing, the volume ratio can be reduced to about 1/6. In addition, the drilling of the switchboard is not required, and the switchboard can be easily mounted anywhere. Material cost for improvement and construction cost can be saved. 3) In the event of a power system failure, the control center can quickly divide the failure detection protection relay. Maintenance staff can be streamlined. 4) Component parts are easily available. 5) Low power consumption because MOS-IC is used for the circuit element.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a circuit according to an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a circuit of a conventional device.

FIG. 3 is a diagram showing a configuration in which a conventional device is improved on an extension of the conventional technology.

FIG. 4 is a diagram showing a structure of a two-winding relay.

FIG. 5 is a diagram showing a circuit in which an open current is detected by a Hall element.

FIG. 6 is a diagram showing details of a circuit portion related to the R-phase overcurrent protection relay 1R indicated by reference numerals 2 and 12 in FIG. 1 and signal waveforms in main parts of the circuit.

FIG. 7 is a diagram showing signal waveforms of respective units shown in FIG. 6 with their time axes aligned so that their temporal correlation can be understood;

FIG. 8 is a diagram showing the appearance of the device of the present invention compactly housed in one case.

[Explanation of symbols]

1R: R-phase overcurrent protection relay 2T: T-phase overcurrent protection relay 3R: R-phase short-circuit detection protection relay 4T: T-phase short-circuit detection protection relay 5: Overcurrent detection integrated relay and operation residual indicator 5a: Overcurrent detection 6: An integrated relay for short-circuit detection and a residual operation indicator 6a: A contact for storing the operation of short-circuit detection and continuously conductive 7: Two windings for integrating over-current and short-circuit detection Relay 7a: Contact that conducts by operation of 7 and returns to time limit 8: Remote monitoring control device 9: Bell alarm circuit 10: Solenoid for opening circuit breaker 11: Contact that conducts when circuit breaker is closed 12, 12a: R-phase overcurrent Operation detector and detection output contact 13, 13a: T-phase overcurrent operation detector and detection output contact 14, 14a: R-phase short-circuit operation detector and detection output contact 15, 15a: T-phase short-circuit operation detector and detection output connection 16, 12 to 15: Common power supply circuit 21: Detection coil 22: Circuit for rectifying the induced voltage of the coil 23: Operational amplifier for amplifying to the voltage level necessary for determination 24: Opening the reference voltage of the comparator to the site A variable resistor that adjusts to the differential value of the current 25: A comparator that determines the presence or absence of an open current 26: A timer that extends the time width of the output voltage of the comparator 27: A light that transmits the output of the timer to the remote monitoring control device 8 Relay 28: Power supply circuit

Continued on the front page (72) Inventor Masahiko Nakamura 1-6-5 Marunouchi, Chiyoda-ku, Tokyo East Japan Railway Company (72) Inventor Shinzo Furuya 1-19-1 Osaki, Shinagawa-ku, Tokyo Eirakuden (72) Inventor Shinichi Okada 1-19-1, Osaki, Shinagawa-ku, Tokyo Eiraku Electric Co., Ltd.

Claims (2)

[Claims] 1. A protection device for each phase (for example, 1R) provided for each of an overcurrent detection and a short-circuit detection is provided with a detection unit to differentiate an open current when the protection relay operates. Means for taking out the value and means for rectifying and amplifying the output voltage of the detecting means (for example, 22, 2,
3) and setting means (2) for setting a voltage level reference.
4), a judging means (25) for judging based on the signals of the amplifying means and the setting means, a means (26) for processing the judged voltage into a DC voltage which continues for a certain period of time, and By combining with the electric means (27), the protection relay operated upon detecting the failure of the power equipment is individually subdivided and transmitted to the remote monitoring control device (8). Current detector. 2. The detecting means comprises a detecting coil (21) and an operation detector (12); the processing means comprises a timer (26); and the relay means comprises an optical relay (27). 2. The current detector according to claim 1, wherein