Monitoring Circuit for the Circuit Breaker Protection Tripping Loop

Abstract

The present invention discloses a monitoring circuit for a breaker protection tripping loop. In this circuit, the positive pole of the DC power supply is respectively connected to one end of the normally open contact of the protection tripping outlet relay and one end of the protection tripping position monitoring lamp. The other end of the protection tripping position monitoring lamp is connected to one end of the protection tripping position relay coil. The other end of the protection tripping position relay coil and the other end of the normally open contact of the protection tripping outlet relay are respectively connected to one end of the protection tripping pressure plate. The other end of the protection tripping pressure plate is connected to one end of the breaker auxiliary normally open contact. The other end of the breaker auxiliary normally open contact is connected to one end of the tripping coil. The other end of the tripping coil is connected to the negative pole of the DC power supply. The monitoring circuit for the breaker protection tripping loop of the present invention can quickly determine whether there is a fault in the in-service breaker protection tripping loop by monitoring the on / off state of the protection tripping position monitoring lamp and the presence or absence of the fault information of "breaker protection tripping loop fault", which is convenient for timely detecting and handling faults.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit breaker protection control, in particular to a monitoring circuit for a circuit breaker protection tripping circuit. Background Art

[0002] As an important electrical equipment in the power system, the high-voltage circuit breaker can connect and disconnect the load current under normal circumstances. When the line and load-side equipment fail to malfunction, it can cut off the faulty line in time to ensure the safety of the power supply system. If the protection tripping circuit of the operating circuit breaker fails and is not discovered and handled in time, when a short circuit fault occurs in the line and load-side equipment, the circuit breaker protection will refuse to operate, and the upper circuit breaker will trip and disconnect the fault point, resulting in large-scale power outages and huge losses. The existing technology's position monitoring circuit of the circuit breaker can only monitor whether there are any abnormalities in the circuit breaker's tripping peripheral components, and cannot effectively monitor the integrity of the entire protection tripping circuit. Therefore, it is necessary to provide a monitoring circuit for the circuit breaker protection tripping circuit, which can timely monitor whether the circuit breaker's protection tripping circuit is complete and reliable, and then take timely treatment measures to ensure that the circuit breaker protection tripping circuit is reliable. Summary of the Invention

[0003] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a monitoring circuit for a circuit breaker protection tripping circuit. The specific technical solution is as follows:

[0004] A monitoring circuit for a circuit breaker protection trip circuit, the circuit comprising: a direct current (DC) power supply, a normally open contact of a protection trip output relay, a protection trip position monitoring light, a protection trip position relay coil, a protection trip pressure plate, a circuit breaker auxiliary normally open contact, and a trip coil; the positive electrode of the DC power supply is respectively connected to one end of the normally open contact of the protection trip output relay and one end of the protection trip position monitoring light; the other end of the protection trip position monitoring light is connected to one end of the protection trip position relay coil; the other end of the protection trip position relay coil and the other end of the normally open contact of the protection trip output relay are respectively connected to one end of the protection trip pressure plate; the other end of the protection trip pressure plate is connected to one end of the circuit breaker auxiliary normally open contact; the other end of the circuit breaker auxiliary normally open contact is connected to one end of the trip coil; the other end of the trip coil is connected to the negative electrode of the DC power supply; the circuit breaker auxiliary normally open contact is in a closed state when the circuit breaker is in a closed state; the resistance of the protection trip position relay coil satisfies the voltage division requirement so that the trip coil cannot be activated.

[0005] In a possible design, the circuit further includes: a trip hold relay coil and a self-holding contact of the trip hold relay; the trip hold relay coil is connected in series between the protection trip pressure plate and the normally open auxiliary contact of the circuit breaker, one end of the self-holding contact of the trip hold relay is connected to the positive pole of the DC power supply, and the other end is connected to the common end of the protection trip pressure plate and the trip hold relay coil.

[0006] In a possible design, the voltage of the DC power supply is 220V.

[0007] In a possible design, the protection trip position monitoring lamp is a yellow LED lamp.

[0008] In a possible design, the protection trip position monitoring lamp, the protection trip position relay coil, the trip hold relay coil, the self-holding contact of the trip hold relay, and the normally open contact of the protection trip outlet relay are all internal components of the microcomputer protection and measurement control device.

[0009] In a possible design, the working state of the protection trip position monitoring lamp is displayed on the microcomputer protection and measurement control device.

[0010] In a possible design, when the circuit breaker is operating normally, if the protection trip circuit of the circuit breaker is incomplete, the protection trip position monitoring lamp goes out, the protection trip position relay coil loses power, the normally closed contact of the protection trip position relay returns, and the input information of "circuit breaker protection trip circuit failure" is connected and displayed on the liquid crystal screen of the microcomputer protection and measurement control device.

[0011] In a possible design, the microcomputer protection and measurement control device establishes a communication connection with the background monitoring microcomputer through a communication cable, and the background monitoring microcomputer can obtain the input fault information of "circuit breaker protection trip circuit failure" on the microcomputer protection and measurement control device, and display it online and give a fault alarm.

[0012] The main advantages of the technical solution of the present invention are as follows:

[0013] The monitoring circuit of the circuit breaker protection trip circuit of the present invention adds a protection trip position monitoring light to the circuit breaker protection trip circuit. Thus, when the circuit breaker is operating normally under load, the positive electrode of the DC power supply passes through the protection trip position monitoring light, the protection trip position relay coil, the protection trip pressure plate, the trip holding relay coil, the circuit breaker auxiliary normally open contact and the trip coil, and finally connects to the negative electrode of the DC power supply. The protection trip circuit is complete and the protection trip position monitoring light is illuminated. If the protection trip circuit fails, that is, the protection trip pressure plate, the trip holding relay coil, the circuit breaker auxiliary normally open contact and the trip coil, or any component in the DC power supply or the connecting line between them fails, the protection trip position monitoring light will go out, indicating that the circuit breaker protection trip circuit is incomplete. At this time, if a short circuit fault occurs in the line or load-side equipment, the circuit breaker will not be able to trip for protection, and the upper circuit breaker will trip and disconnect the fault point, resulting in a large-scale power outage and huge losses. Therefore, the operation and maintenance personnel can obtain the circuit breaker protection trip circuit fault information in time and handle it quickly by monitoring the online alarm information of "circuit breaker protection trip circuit fault" on the background monitoring computer or checking the extinction of the protection trip position monitoring light on the microcomputer protection measurement and control device on site, thus avoiding the expansion of the scope of the accident. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0015] Figure 1 A monitoring circuit diagram of a circuit breaker protection tripping circuit provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0018] The embodiment of the present invention provides a monitoring circuit for a circuit breaker protection trip circuit, as shown in the attached Figure 1As shown in the figure, the circuit includes: a DC power supply KM, a normally open contact BTJ of a protection trip outlet relay, a protection trip position monitoring lamp HY, a protection trip position relay coil BTWJ, a protection trip pressure plate LP1, a normally open auxiliary contact QF of a circuit breaker, and a trip coil TQ; the positive pole +KM of the DC power supply is respectively connected to one end of the normally open contact BTJ of the protection trip outlet relay and one end of the protection trip position monitoring lamp HY, the other end of the protection trip position monitoring lamp HY is connected to one end of the protection trip position relay coil BTWJ, the other end of the protection trip position relay coil BTWJ and the other end of the normally open contact BTJ of the protection trip outlet relay are respectively connected to one end of the protection trip pressure plate LP1, the other end of the protection trip pressure plate LP1 is connected to one end of the normally open auxiliary contact QF of the circuit breaker, the other end of the normally open auxiliary contact QF of the circuit breaker is connected to one end of the trip coil TQ, and the other end of the trip coil TQ is connected to the negative pole -KM of the DC power supply; the normally open auxiliary contact QF of the circuit breaker is in a closed state when the circuit breaker is in the closing state, and the resistance of the protection trip position relay coil BTWJ satisfies the voltage division such that the trip coil TQ cannot be started.

[0019] The working principle of the monitoring circuit of the circuit breaker protection trip circuit provided by the embodiment of the present invention will be described below:

[0020] In this circuit, the loop where the DC power supply KM, the normally open contact BTJ of the protection trip outlet relay, the protection trip pressure plate LP1, the normally open auxiliary contact QF of the circuit breaker, and the trip coil TQ are located constitutes the circuit breaker protection trip circuit. When the circuit breaker is operating normally, the normally open auxiliary contact QF of the circuit breaker is closed. When a short circuit fault occurs in the line and the load equipment, the normally open contact BTJ of the protection trip outlet relay in the protection device closes, connecting the circuit breaker protection trip circuit. The trip coil TQ is energized, the trip electromagnet acts, driving the operating mechanism to act, realizing the circuit breaker protection trip, and the circuit breaker disconnects to cut off the fault current. By connecting the protection trip position monitoring lamp HY and the protection trip position relay coil BTWJ in parallel with the normally open contact BTJ of the protection trip outlet relay to form a monitoring loop, when there is no fault in the protection trip pressure plate LP1, the normally open auxiliary contact QF of the circuit breaker, the trip coil TQ, and the DC power supply, the protection trip position monitoring lamp HY is connected to the DC power supply KM and lights up. And at this time, due to the voltage division effect of the protection trip position relay coil BTWJ, the voltage obtained by the trip coil TQ is very low, far lower than the starting voltage of the trip coil, so the circuit breaker trip operation will not be triggered. When one or more of the protection trip pressure plate LP1, the normally open auxiliary contact QF of the circuit breaker, the trip coil TQ, and the DC power supply have a fault, the protection trip position monitoring lamp HY goes out. Whether the circuit breaker protection trip circuit has a fault can be quickly determined by the on and off of the protection trip position monitoring lamp HY, and the working state of the trip circuit will not be disturbed.

[0021] The monitoring circuit for the circuit breaker protection trip circuit provided by the embodiment of the present invention adds a protection trip position monitoring light HY to the circuit breaker protection trip circuit. Thus, when the circuit breaker is operating normally under load, the positive pole +KM of the DC power supply passes through the protection trip position monitoring light HY, the protection trip position relay coil BTWJ, the protection trip pressure plate LP1, the circuit breaker auxiliary normally open contact QF, and the tripping coil TQ, and finally connects to the negative pole -KM of the DC power supply. The protection trip circuit is complete, and the protection trip position monitoring light HY lights up. If the protection trip circuit fails, the protection trip position monitoring light HY will go out, indicating that the protection trip circuit is incomplete. At this time, if a short circuit fault occurs in the line or load-side equipment, the circuit breaker will not trip for protection, and the upper circuit breaker will trip to disconnect the fault point, resulting in a large-scale power outage and huge losses.

[0022] The protection trip monitoring light HY may be an LED light, for example, a yellow LED light.

[0023] Furthermore, the circuit also includes a trip holding relay coil TBJ and a trip holding relay self-holding contact TBJ1; the trip holding relay coil TBJ is connected in series between the protection trip pressure plate LP1 and the circuit breaker auxiliary normally open contact QF, and one end of the trip holding relay self-holding contact TBJ1 is connected to the positive pole +KM of the DC power supply, and the other end is connected to the common end of the protection trip pressure plate LP1 and the trip holding relay coil TBJ.

[0024] With this configuration, when the trip-hold relay coil TBJ is energized, the trip-hold relay's self-holding contact TBJ1 closes. This prevents the trip coil TQ from failing to operate properly and reliably due to short closing times or rapid return of the trip contacts during normal opening operations, or due to oscillation or inadequate closing of the normally open contact BTJ of the protection trip output relay during short-circuit tripping. Furthermore, the trip-hold relay's self-holding contact TBJ1 connects the DC power supply KM, powering the protection trip circuit and improving the reliability of the circuit breaker's normal opening and protection tripping circuits.

[0025] The protection trip position relay coil BTWJ is a voltage-type coil, the trip holding relay is a current-type relay, and the trip coil TQ is a voltage-activated element. The resistance of the protection trip position relay coil BTWJ is over 100 times that of the trip coil TQ.

[0026] The monitoring circuit of the breaker protection tripping loop during operation is continuously conducting. The protection tripping position relay coil BTWJ and the opening coil TQ are connected in series (the resistance of the tripping holding relay coil TBJ is very small and can be ignored), and the two jointly bear a voltage of 220V. However, the resistance of the protection tripping position relay coil BTWJ is very large. For example, the resistance value of the protection tripping position relay coil BTWJ is 18.27 kΩ, while the resistance of the opening coil TQ is only more than 100 Ω. The former is much larger than the latter. Therefore, the voltage shared by the opening coil TQ is very low. Since the opening coil TQ is a voltage-activated component, it is not sufficient to cause the opening coil TQ to operate. Similarly, because the tripping holding relay in the monitoring circuit is a current-type relay and its coil resistance is very small, even if the circuit is connected, the current in this monitoring circuit is very low, generally a dozen mA, and the tripping holding relay will not operate. The self-holding contact of the tripping holding relay will not be closed, and thus will not cause the opening coil TQ to operate. In addition, the protection tripping position relay coil BTWJ of this circuit is a voltage coil. The problem of long-term power-on has been considered in the design, and it will not burn out by itself, with high safety and stability.

[0027] In the embodiment of the present invention, except for the breaker 1DK, the protection tripping pressure plate LP1, the auxiliary normally open contact QF of the breaker, and the opening coil TQ at the DC power supply KM, the protection tripping position monitoring lamp HY, the protection tripping position relay coil BTWJ, the coil TBJ of the tripping holding relay and its self-holding contact TBJ1, and the normally open contact BTJ of the protection tripping outlet relay are all internal components of the microcomputer protection and measurement and control device. Among them, the protection tripping position monitoring lamp HY is installed on the panel of the microcomputer protection and measurement and control device, and the protection tripping position relay coil BTWJ is installed on the circuit board.

[0028] Optionally, when the protection tripping loop of the breaker is incomplete, the protection tripping position monitoring lamp HY goes out. At the same time, the coil BTWJ of the protection tripping position relay loses power, the normally closed contact of the protection tripping position relay returns, the input quantity information of "breaker protection tripping loop fault" is connected, and it is displayed on the LCD screen of the microcomputer protection and measurement and control device.

[0029] Optionally, the microcomputer protection and measurement and control device is connected to the background monitoring microcomputer through a communication cable. The background monitoring microcomputer can obtain the input quantity fault information of "breaker protection tripping loop fault" on the microcomputer protection and measurement and control device. With such a setting, it is convenient to quickly obtain the breaker protection tripping loop fault situation in a non-site area. The communication cable can be connected to the communication interface on the microcomputer protection and measurement and control device to achieve connection with the background monitoring microcomputer. The microcomputer protection and measurement and control device and the background monitoring microcomputer are connected with a communication management machine. Through the communication management machine, the information collected on each microcomputer protection and measurement and control device can be summarized, processed, and then communicated and transmitted to the background monitoring microcomputer. To achieve the online display of the fault information of "breaker protection tripping loop fault" on the background monitoring microcomputer.

[0030] Furthermore, the background monitoring microcomputer can also be connected to an alarm device. After receiving the fault information of "circuit breaker protection trip circuit failure", the background monitoring microcomputer issues an alarm message through the alarm device to alert the staff. The alarm device can be an audible and visual alarm, etc.

[0031] In summary, for the monitoring circuit of the circuit breaker protection trip circuit provided by the embodiment of the present invention, when the circuit breaker is operating normally and energized, the protection trip position monitoring lamp HY in the monitoring circuit of the circuit breaker protection trip circuit lights up, indicating that the circuit breaker protection trip circuit is complete and abnormal-free. If there are faults such as loose connection and poor contact of the connection point of the protection trip pressure plate LP1 contact, the trip holding relay coil TBJ of the microcomputer protection and control device, the auxiliary normally open contact QF of the circuit breaker, and the trip coil TQ, or if the protection trip pressure plate LP1 is forgotten to be closed after equipment maintenance test and before power transmission, the protection trip position monitoring lamp HY on the microcomputer protection and control device cannot light up. At the same time, the background monitoring microcomputer will also issue the fault information of "circuit breaker protection trip circuit failure", indicating that the protection trip circuit of the circuit breaker is incomplete and there is a fault, and corresponding measures should be taken in time to ensure that when a short-circuit fault occurs in the line and the load-side equipment, the circuit breaker protection trip can be reliably realized, the fault line can be cut off, and the expansion of the accident range and the impact on the safety of the power supply system can be avoided.

[0032] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. In addition, in this article, "front", "rear", "left", "right", "upper" and "lower" are all referenced with the placement state shown in the drawings.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A monitoring circuit for a breaker protection tripping circuit, characterized in that, The circuit includes: a DC power supply, normally open contacts of a protection trip outlet relay, a protection trip position monitoring lamp, a protection trip position relay coil, a protection trip pressure plate, normally open auxiliary contacts of a circuit breaker, and a trip coil; The positive pole of the DC power supply is respectively connected to one end of the normally open contacts of the protection trip outlet relay and one end of the protection trip position monitoring lamp. The other end of the protection trip position monitoring lamp is connected to one end of the protection trip position relay coil. The other end of the protection trip position relay coil and the other end of the normally open contacts of the protection trip outlet relay are respectively connected to one end of the protection trip pressure plate. The other end of the protection trip pressure plate is connected to one end of the normally open auxiliary contacts of the circuit breaker. The other end of the normally open auxiliary contacts of the circuit breaker is connected to one end of the trip coil. The other end of the trip coil is connected to the negative pole of the DC power supply; The normally open auxiliary contacts of the circuit breaker are in a closed state when the circuit breaker is in the closing state; The resistance of the protection trip position relay coil satisfies voltage division such that the trip coil cannot be started; The circuit further includes: a trip holding relay coil and a self-holding contact of the trip holding relay; The trip holding relay coil is connected in series between the protection trip pressure plate and the normally open auxiliary contacts of the circuit breaker. One end of the self-holding contact of the trip holding relay is connected to the positive pole of the DC power supply, and the other end is connected to the common end of the protection trip pressure plate and the trip holding relay coil; The protection trip position relay coil is a voltage coil, the trip holding relay is a current-type relay, the trip coil is a voltage starting element. When the protection trip position relay coil is turned on, the trip holding relay and the trip coil will not operate.

2. The monitoring circuit of the breaker protection tripping loop according to claim 1, characterized in that The voltage of the DC power supply is 220V.

3. The monitoring circuit of the circuit breaker protection tripping loop according to claim 1, wherein The protection trip position monitoring lamp is a yellow light-emitting LED lamp.

4. The monitoring circuit of the breaker protection tripping circuit according to claim 1, characterized in that, The protection trip position monitoring lamp, the protection trip position relay coil, the trip holding relay coil, the self-holding contact of the trip holding relay, and the normally open contacts of the protection trip outlet relay are all internal components of the microcomputer protection and measurement and control device.

5. The monitoring circuit of the breaker protection tripping loop according to claim 4, characterized in that, The working state of the protection trip position monitoring lamp is displayed on the microcomputer protection and measurement and control device.

6. The monitoring circuit of the breaker protection tripping circuit according to claim 5, characterized in that, When the circuit breaker is working normally, if the protection trip circuit of the circuit breaker is incomplete, the protection trip position monitoring lamp goes out, the protection trip position relay coil loses power, the normally closed contacts of the protection trip position relay return, and the input quantity information of "circuit breaker protection trip circuit fault" is connected and displayed on the liquid crystal screen of the microcomputer protection and measurement and control device.

7. The monitoring circuit of the breaker protection tripping loop according to claim 6, characterized in that The microcomputer protection and measurement and control device establishes a communication connection with the background monitoring microcomputer through a communication cable. The background monitoring microcomputer can obtain the input quantity information of "circuit breaker protection trip circuit fault" on the microcomputer protection and measurement and control device to achieve online display and fault alarm.

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