Anti-adhesion protection device and method for power coil
By introducing protection devices such as knife switches, time relays, and intermediate relays into the circuit breaker coil, the coil's power supply can be cut off at specific times, solving the problems of coil sticking and burning and inaccurate position judgment. This improves the safety and ease of operation of the power system and reduces equipment maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- STATE GRID HENAN ELECTRIC POWER CO YEXIAN POWER SUPPLY CO
- Filing Date
- 2025-12-01
- Publication Date
- 2026-05-01
AI Technical Summary
Circuit breaker coils are prone to burning out due to sticking, and inaccurate position judgments can be caused by control circuit faults. Existing protection devices cannot effectively solve this problem, which affects the safe and stable operation of the power system.
The system employs a protection device that includes a knife switch, a time relay, an intermediate relay, and a coil. By periodically cutting off the power supply to the coil, combined with the overload/short circuit protection function of the circuit breaker, it ensures that the coil is de-energized promptly after the closing/opening operation. The system utilizes the coordination of normally open and normally closed contacts to achieve timed power supply control of the coil.
It extends the coil's lifespan by 3-5 times, reduces equipment replacement costs, narrows the scope of fault diagnosis, improves fault handling efficiency, reduces the risk of human error, and is inexpensive, making it easy to promote and apply in different power systems.
Smart Images
Figure CN121965404A_ABST
Abstract
Description
A power coil anti-sticking protection device and method Technical Field
[0001] This invention relates to the field of power equipment protection technology, and in particular to a power coil anti-adhesion protection device and method. Background Technology
[0002] In the daily operation of power systems, circuit breakers are key devices for realizing circuit switching and fault isolation, and their operational reliability directly affects the safety of power supply. Under normal operating conditions, the closing / opening operation of a circuit breaker relies on coil drive: when closing, the closing coil is energized, and after the action is completed, the closing circuit is disconnected through the auxiliary contacts of the circuit breaker, and the coil returns to its original position; the opening operation logic is the same.
[0003] However, in actual production and operation, three types of problems can easily lead to coil failure in the control circuit: First, contact adhesion, where auxiliary contacts stick together due to long-term arc erosion and mechanical wear, making it impossible to disconnect the circuit; second, unstable secondary operating voltage, where voltage fluctuations cause abnormal operation of the auxiliary contacts, resulting in circuit disconnection failure; and third, primary mechanism jamming, where the circuit breaker's mechanical mechanism jams, preventing the auxiliary contacts from switching with the mechanism's movement, causing the circuit to remain conductive. All of these problems will cause the coil to remain continuously energized, leading to a rapid increase in temperature and ultimately burning out the coil. This not only damages the equipment but may also trigger serious faults such as short circuits in the control circuit and circuit breaker malfunctions.
[0004] Furthermore, when a control circuit fault occurs and the protection device reports a "control circuit open" signal, the existing logic cannot determine the circuit breaker's position, i.e., whether the circuit breaker is in the closed or open position. This is because the "control circuit open" determination relies on the connection of the closing relay (HWJ) and the opening relay (TWJ) in series; the signal is only set to 1 when both relays are simultaneously de-energized. If the coil remains energized due to a fault, the HWJ or TWJ will be in an abnormally energized state, disrupting the normal determination logic. This prevents the on-duty dispatcher from accurately determining the circuit breaker's real-time position, delaying fault handling, expanding the scope of the fault's impact, and affecting the efficiency of subsequent handling. Currently, the industry lacks protection devices that are simple in structure, low in cost, and can simultaneously solve both of these problems, representing a significant technological gap. Summary of the Invention
[0005] The purpose of this invention is to provide a power coil anti-adhesion protection device and method to prevent the closing coil and opening coil of a circuit breaker from sticking and burning due to continuous energization. At the same time, it helps to improve the accuracy of circuit breaker position judgment when a "control circuit disconnection" fault occurs, thus providing a guarantee for the safe and stable operation of the power system.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: The present invention provides a power coil anti-adhesion protection device, comprising: a knife switch, a time relay, an intermediate relay, a coil, and a circuit breaker; the time relay integrates a normally open contact; the intermediate relay integrates a normally closed contact; one end of the knife switch is electrically connected to a DC input point, and the other end is electrically connected to the power input terminal of the time relay, one end of the normally open contact, and one end of the normally closed contact; the power output terminal of the time relay is electrically connected to a DC output point; the other end of the normally open contact is electrically connected to the power input terminal of the intermediate relay, and the power output terminal of the intermediate relay is electrically connected to the DC output point; the other end of the normally closed contact is electrically connected to one end of the coil, and the other end of the coil is electrically connected to the DC output point; the circuit breaker is connected in series between the DC input point and the knife switch.
[0007] In some embodiments, the system further includes a power conversion module; the power conversion module is connected in parallel across the two ends of the time relay.
[0008] In some embodiments, the time relay is an energized delay type time relay.
[0009] In some embodiments, two sets of normally open contacts and two sets of normally closed contacts are provided, and the two sets of normally open contacts and normally closed contacts are connected in parallel.
[0010] In some embodiments, the device further includes a first diode; the first diode is connected in series between the knife switch and the time relay.
[0011] In some embodiments, the device further includes a second diode connected in parallel across the two ends of the coil.
[0012] This invention also provides a method for preventing the sticking of power coils, using the protection device described above, comprising the following steps: S100, activating the protection device and closing the knife switch, at which time the time relay and the coil are synchronously energized, and the coil drives the circuit breaker to complete the closing / opening action; S200, the time relay enters the delay stage, and after the preset delay time is reached, its normally open contact automatically closes, the power supply circuit of the intermediate relay is connected, and the intermediate relay starts to work; S300, the normally closed contact of the intermediate relay automatically opens, the power supply circuit of the coil is cut off, and the coil stops being energized.
[0013] The power coil anti-adhesion protection device and method provided in this embodiment of the invention have the following beneficial effects: 1. Equipment protection: By periodically cutting off the power supply to the coil, the problem of coil burnout due to continuous energization is fundamentally solved. Actual measurements show that the coil's service life can be extended by 3-5 times, reducing equipment replacement costs. Simultaneously, the overload / short circuit protection function of the circuit breaker can prevent the fault from escalating and reduce system maintenance costs. 2. Fault auxiliary judgment: When the protection device is working normally, the coil's energization time is strictly controlled within 3-5 seconds. If the "control circuit disconnection" signal is triggered, the coil is in a non-energized state (which can be detected by a multimeter). This can assist the dispatcher in eliminating "misjudgment of location caused by continuous coil energization," narrowing the scope of fault investigation and improving fault handling efficiency. 3. Efficiency: The core control of the protection device relies solely on the on / off state of the knife switch, eliminating the need for complex parameter settings or programming. On-site personnel can operate it proficiently after simple training, reducing the risk of human error. 4. Cost-effectiveness: All components are standardized mass-produced products in the power industry, with wide procurement channels and low prices (e.g., the unit price of a JS14P time relay is approximately 50-80 yuan, and the unit price of a DZ47 circuit breaker is approximately 20-30 yuan). The circuit design is simple, no special equipment is required during manufacturing, labor costs are low, and the overall cost is far lower than that of existing complex protection devices. 5. It provides a protection device that is easy to operate, has low manufacturing costs, and strong voltage adaptability, making it easy to promote and apply in power systems of different scales and voltage levels. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual process of the method, etc. involved in the embodiments of this disclosure.
[0015] Figure 1 is a schematic diagram of the principle of a power coil anti-adhesion protection device according to some embodiments of the present disclosure. Detailed Implementation
[0016] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.
[0017] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.
[0018] This invention provides a power coil L1 anti-sticking protection device, as shown in Figure 1, including: knife switch S1, time relay KT1, intermediate relay M, coil L1 and circuit breaker.
[0019] In some embodiments, the time relay KT1 integrates a normally open contact, and the intermediate relay M integrates a normally closed contact.
[0020] Under normal conditions, the normally open contact is open, the circuit is not continuous, and the normally closed contact is closed, the circuit is continuous. Time relay KT1 controls the normally open contact to close after a preset time, thus connecting the circuit. Intermediate relay M controls the normally closed contact to open, thus disconnecting the circuit.
[0021] In some embodiments, one end of the knife switch S1 is electrically connected to the DC input point, and the other end is electrically connected to the power input terminal, one end of the normally open contact, and one end of the normally closed contact of the time relay KT1, respectively.
[0022] In some embodiments, the power output terminal of the time relay KT1 is electrically connected to the DC output point.
[0023] In this invention, the DC input point → knife switch S1 → time relay KT1 → DC output point constitute the main power supply circuit of time relay KT1.
[0024] The knife switch S1 serves as the main control switch for the protection device, enabling the overall power-on and power-off control of the protection device, and is easy to operate.
[0025] In some examples, the time relay KT1 is an energized delay type time relay.
[0026] For example, the time relay KT1 has the model number JS14P DC220V.
[0027] The time relay KT1 adopts a power-on delay design. Its core function is to control the closing of the normally open contact according to a preset time, thereby controlling the connection of the intermediate relay M and realizing the timed disconnection of the power supply to the coil L1.
[0028] For example, the protection device uses DC220V power supply. Therefore, the DC input point is +110V DC input point and the DC output point is -110V DC output point.
[0029] In some embodiments, the other end of the normally open contact is electrically connected to the power input terminal of the intermediate relay M, and the power output terminal of the intermediate relay M is electrically connected to the DC output point.
[0030] In this invention, the DC input point → knife switch S1 → normally open contact → intermediate relay M → DC output point, when the normally open contact is closed, forms the power supply circuit for the intermediate relay M.
[0031] The function of the intermediate relay M is to control the opening of the normally closed contact, thereby realizing the timed disconnection of the power supply to coil L1.
[0032] In some embodiments, the other end of the normally closed contact is electrically connected to one end of the coil L1, and the other end of the coil L1 is electrically connected to the DC output point.
[0033] In this invention, the DC input point → knife switch S1 → normally closed contact → coil L1 → DC output point constitute the power supply circuit for coil L1.
[0034] Coil L1 is the object protected by the protection device, and the circuit breaker is activated by switching the power on and off.
[0035] In some embodiments, the circuit breaker is connected in series between the DC input point and the knife switch S1. The input terminal of the circuit breaker is electrically connected to the DC input point, and the output terminal is electrically connected to the knife switch S1. The circuit breaker covers the entire power supply circuit of the protection device, and automatically trips to cut off the power supply in the event of a fault, thereby achieving overload and short-circuit fault protection.
[0036] For example, the circuit breaker model is DZ47 2P C16, and the manufacturer is Delixi.
[0037] The working principle of the power coil anti-adhesion protection device provided in this embodiment of the invention is as follows: The working process of the protection device is divided into three stages, with clear logic and matching the circuit breaker operation cycle: 1. Standby stage: The knife switch S1 is in the open state, the entire protection device is not powered, and the time relay KT1, intermediate relay M, and coil L1 are all in a de-energized sleep state with no energy loss; 2. Operation driving stage: When the circuit breaker needs to operate, the knife switch S1 is closed, and the main power supply circuit and the coil L1 power supply circuit are simultaneously connected. After the coil L1 is energized, it generates electromagnetic force, driving the circuit breaker to complete the closing or opening operation. 3. Protection cut-off stage: Time relay KT1 starts timing after being energized. When time relay KT1 reaches the preset delay time (3-5 seconds, which can be finely adjusted according to the circuit breaker's operating speed), its internal delay mechanism is activated, the normally open contact is turned on, the intermediate relay M is energized, and then the normally closed contact is opened, the control circuit of coil L1 is cut off, and coil L1 stops being energized to avoid coil L1 sticking due to prolonged energization. At this time, time relay KT1 is still energized, but only maintains its own operation, with low energy consumption and does not affect system safety.
[0038] The power coil anti-adhesion protection device and method provided in this embodiment of the invention have the following beneficial effects: 1. Equipment protection: By periodically cutting off the power supply to the coil, the problem of coil burnout due to continuous energization is fundamentally solved. Actual measurements show that the coil's service life can be extended by 3-5 times, reducing equipment replacement costs. Simultaneously, the overload / short circuit protection function of the circuit breaker can prevent the fault from escalating and reduce system maintenance costs. 2. Fault auxiliary judgment: When the protection device is working normally, the coil's energization time is strictly controlled within 3-5 seconds. If the "control circuit disconnection" signal is triggered, the coil is in a non-energized state (which can be detected by a multimeter). This can assist the dispatcher in eliminating "misjudgment of location caused by continuous coil energization," narrowing the scope of fault investigation and improving fault handling efficiency. 3. Efficiency: The core control of the protection device relies solely on the on / off state of the knife switch, eliminating the need for complex parameter settings or programming. On-site personnel can operate it proficiently after simple training, reducing the risk of human error. 4. Cost-effectiveness: All components are standardized mass-produced products in the power industry, with wide procurement channels and low prices (e.g., the unit price of a JS14P time relay is approximately 50-80 yuan, and the unit price of a DZ47 circuit breaker is approximately 20-30 yuan). The circuit design is simple, no special equipment is required during manufacturing, labor costs are low, and the overall cost is far lower than that of existing complex protection devices. 5. It provides a protection device that is easy to operate, has low manufacturing costs, and strong voltage adaptability, making it easy to promote and apply in power systems of different scales and voltage levels.
[0039] In some embodiments, the protection device further includes a power conversion module connected in parallel across the two ends of the time relay KT1.
[0040] For example, the power conversion module is located between the knife switch S1 and the time relay KT1.
[0041] This invention achieves multi-voltage level adaptation through a power conversion module, eliminating the need for circuit redesign and reducing adaptation costs. It can meet the needs of mainstream DC control circuits such as DC24V-DC220V and its application scope covers low-voltage power distribution, substations, new energy power plants and other scenarios.
[0042] For example, the power conversion module is a power conversion module that converts 220V DC to 24V DC.
[0043] Normally, the protection device uses DC220V power supply. By setting up a power conversion module, the protection device can be directly connected to a general power supply, and the general power supply can be converted to a power supply that is compatible with the DC voltage level of the time relay KT1, so as to realize the adaptive operation of different DC voltage levels.
[0044] In some embodiments, two sets of normally open contacts and two sets of normally closed contacts are provided, and the two sets of normally open contacts and normally closed contacts are connected in parallel.
[0045] For example, the normally open contacts include a first normally open contact KT1a and a second normally open contact KT1b, which are connected in parallel. The normally closed contacts include a first normally closed contact M1 and a second normally closed contact M2, which are also connected in parallel. This ensures that the circuit can carry a larger current.
[0046] In some embodiments, the protection device further includes a first diode D1, which is connected in series between the knife switch S1 and the time relay KT1.
[0047] For example, the anode of the first diode D1 is electrically connected to the knife switch S1, and the cathode is electrically connected to the power input terminal of the power conversion module.
[0048] In some embodiments, the protection device further includes a second diode D2, which is connected in parallel across the two ends of the coil L1.
[0049] The first diode D1 and the second diode D2 are used to detect whether the circuit is connected correctly. If the circuit is connected correctly, both the first diode D1 and the second diode D2 will be turned on.
[0050] For example, both the first diode D1 and the second diode D2 are light-emitting diodes. When the circuit is connected correctly, both the first diode D1 and the second diode D2 can emit light.
[0051] This invention also provides a method for preventing the sticking of power coils, which uses the protection device described above and includes steps S100-S300.
[0052] S100, activate the protection device and close the knife switch S1. At this time, the time relay KT1 and the coil L1 are energized synchronously, and the coil L1 drives the circuit breaker to complete the closing / opening action.
[0053] Before step S100, refer to the schematic diagram of the device (Figure 1) to complete the wiring connection of each component, and ensure that the wiring terminals are tight, have good contact, and are free from loose or incorrect connections.
[0054] S200, time relay KT1 enters the delay stage. After the preset delay time is reached, its normally open contact automatically closes, the power supply circuit of intermediate relay M is connected, and intermediate relay M starts to work.
[0055] S300, the normally closed contact of the intermediate relay M automatically opens, the power supply circuit of coil L1 is cut off, and coil L1 stops being energized.
[0056] In addition to the steps S100-S300 above, if the protection device is not in use or needs maintenance, the knife switch S1 can be disconnected to cut off the power supply to the entire protection device and ensure operational safety.
[0057] 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 it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.
Claims
1. A power coil anti-sticking protection device, characterized in that, include: The device comprises a knife switch, a time relay, an intermediate relay, a coil, and a circuit breaker; the time relay integrates a normally open contact; the intermediate relay integrates a normally closed contact; one end of the knife switch is electrically connected to a DC input point, and the other end is electrically connected to the power input terminal of the time relay, one end of the normally open contact, and one end of the normally closed contact; the power output terminal of the time relay is electrically connected to a DC output point; the other end of the normally open contact is electrically connected to the power input terminal of the intermediate relay, and the power output terminal of the intermediate relay is electrically connected to the DC output point; the other end of the normally closed contact is electrically connected to one end of the coil, and the other end of the coil is electrically connected to the DC output point; the circuit breaker is connected in series between the DC input point and the knife switch.
2. The power coil anti-adhesion protection device as described in claim 1, characterized in that, Also includes: Power conversion module; The power conversion module is connected in parallel across the two ends of the time relay.
3. The power coil anti-adhesion protection device as described in claim 1, characterized in that, The time relay is a power-on delay type time relay.
4. The power coil anti-adhesion protection device as described in claim 1, characterized in that, The normally open contact and the normally closed contact are provided in two sets, and the two sets of normally open contacts and normally closed contacts are connected in parallel.
5. The power coil anti-adhesion protection device as described in claim 1, characterized in that, Also includes: The first diode is connected in series between the knife switch and the time relay.
6. The power coil anti-adhesion protection device as described in claim 1, characterized in that, Also includes: Second diode; The second diode is connected in parallel across the two ends of the coil.
7. A method for preventing the sticking of power coils, characterized in that, The protective device as described in any one of claims 1-6 is adopted. The process includes the following steps: S100, the protection device is activated and the knife switch is closed. At this time, the time relay and the coil are synchronously energized, and the coil drives the circuit breaker to complete the closing / opening action; S200, the time relay enters the delay stage. After the preset delay time is reached, its normally open contact automatically closes, the power supply circuit of the intermediate relay is connected, and the intermediate relay starts to work; S300, the normally closed contact of the intermediate relay automatically opens, the power supply circuit of the coil is cut off, and the coil stops being energized.