Automatic cooling circulation system and method for high-voltage direct-current circuit breaker

Abstract

The invention discloses an automatic cooling circulation system and method for a high-voltage direct-current circuit breaker, and the system comprises a machine body water jacket nested at the outer side of the circuit breaker, takes away the heat generated by the circuit breaker through the circulating flow of a cooling liquid, provides cooling liquid circulation power through a water pump, and increases the heat dissipation area of the cooling liquid through a heat dissipation net. Heat exchange between cooling liquid and air is conducted, a fan is used for blowing air to a heat dissipation net, heat dissipation is accelerated, meanwhile, electric arcs of a circuit breaker are lengthened through blowing, impedance of the circuit breaker is increased, the system is connected into a diaphragm type expansion tank and a water tank, and the pressure in a cooling circulation system pipeline is adjusted. The system is high in automation operation degree, the fan and the water pump can be prevented from being in a high-power working state under the condition that the temperature is not high, the service life of equipment is prolonged, meanwhile, the system can meet the requirements of different temperature working conditions, and the application range is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage direct current circuit breaker cooling, and in particular to an automatic cooling circulation system and method for a high-voltage direct current circuit breaker. Background Art

[0002] With the rapid rise of the new energy industry, in order to alleviate the huge carbon emission pressure brought by thermal power generation and implement the concept of environmental protection and sustainable development, the proportion of new energy power generation connected to the power grid has been increasing in recent years. As the main way of new energy access, high-voltage direct current transmission has become the transmission development trend of modern power grids. The transmission capacity and transmission distance of high-voltage direct current are constantly improving. The direct current transmission lines using overhead lines are greatly affected by the climate and environment along the line, and the probability of single-pole grounding short circuit faults in the lines is relatively high. Due to the lack of self-clearing capability of direct current transmission lines, circuit breakers are usually selected to cut off the lines for fault clearing to avoid greater harm to the stability of the entire system. Therefore, temperature control protection of circuit breakers is one of the important aspects.

[0003] At present, the temperature control and heat dissipation of circuit breakers generally adopt air cooling or water cooling. Water cooling has the advantages of small size, high heat dissipation efficiency and easy replacement of various components. However, it also has problems such as poor intelligent temperature control effect and pressure burst of pipelines, which cause unstable pressure in the cooling system, increased temperature and frequent failures of circuit breakers. At the same time, the cooling system in this field is unable to cool well according to different temperatures, and cannot leave enough margin during arc burning to prevent the cooling system from bursting due to excessive temperature.

[0004] For example, the patent document with application number 202211118327.X discloses an outdoor solid-state DC circuit breaker cooling system and cooling method, the system comprising: an oil tank and a circulating cooling mechanism; a solid-state circuit breaker body is placed in the oil tank, and insulating liquid is injected into the oil tank. The insulating liquid absorbs the heat generated by the solid-state circuit breaker body and vaporizes into steam. The steam is liquefied into insulating liquid through the circulating cooling mechanism and flows back into the oil tank, thereby automatically circulating and cooling the solid-state circuit breaker body.

[0005] The entire circulation system of this application is a completely closed system. The internal insulating liquid is heated unevenly, resulting in density and pressure differences. The gas enters the condenser and liquefies into liquid, and naturally flows back to the bottom of the oil tank due to gravity difference, so that the insulating liquid is converted between vapor and liquid states and circulates automatically. The circuit breaker's cooling system, primary electrical system, secondary energy supply system, etc. adopt a fully sealed design, which is completely isolated from the atmosphere, maintenance-free, and can be installed, debugged, and operated outdoors or at sea. However, its DC circuit breaker cooling system also has problems with low intelligent temperature control and poor pipeline pressure temperature control. Summary of the invention

[0006] In view of the above problems, the object of the present invention is to provide an automatic cooling circulation system and method for a high-voltage DC circuit breaker, which cools the circuit breaker according to different temperatures, maintains stable pipeline pressure, prevents the cooling system from bursting due to excessive temperature, and assists in arc extinguishing.

[0007] The object of the present invention can be achieved by the following technical solution: A high-voltage DC circuit breaker automatic cooling circulation system, comprising:

[0008] The water jacket is nested outside the circuit breaker and removes the heat generated by the circuit breaker through the circulation of coolant;

[0009] Water pump, providing coolant circulation power;

[0010] Heat dissipation network: increase the heat dissipation area of ​​the coolant and perform heat exchange between the coolant and the air;

[0011] The fan blows air to the heat dissipation net to speed up the heat dissipation, and at the same time uses the air to lengthen the circuit breaker arc and increase the circuit breaker impedance;

[0012] The diaphragm expansion tank is connected to the cooling circulation system to adjust the pressure in the cooling circulation system pipeline.

[0013] As a further solution of the present invention, it also includes:

[0014] Pressure sensor, measuring the pressure in the cooling circulation system pipeline;

[0015] Temperature sensor, measuring the coolant temperature in the cooling circulation system pipeline;

[0016] The water tank is connected to the cooling circulation system to regulate the coolant in the cooling circulation system pipeline;

[0017] The pressure valve controls the connection between the water tank and the cooling circulation system according to the pressure in the cooling circulation system pipeline.

[0018] As a further solution of the present invention, the water pump and the fan are electrically connected to a pressure sensor and a temperature sensor, and the water pump and the fan adjust the rotation speed according to the pressure sensor and the temperature sensor signals.

[0019] As a further solution of the present invention, the diaphragm expansion tank is connected to an automatic exhaust valve.

[0020] As a further solution of the present invention, the water pump and the fan are electrically connected to a circuit breaker to disconnect the command signal.

[0021] As a further solution of the present invention, the outlet and the inlet of the water jacket of the machine body are connected with stop valves, and the stop valves control the on-off of the pipeline.

[0022] A high-voltage DC circuit breaker automatic cooling circulation method applied to the above system comprises:

[0023] The heat generated by the circuit breaker is removed by circulating coolant in the cooling circulation system, and the pressure of the cooling circulation system pipeline is adjusted by using a diaphragm expansion tank and / or a water tank to maintain a stable pressure in the cooling circulation system pipeline.

[0024] As a further solution of the present invention, the step of adjusting the pressure of the cooling circulation system pipeline comprises the following steps:

[0025] When the circuit is working normally, the water pump provides coolant circulation power to complete the water circulation between the water jacket of the machine body and the heat dissipation network, and the fan does not work;

[0026] When the temperature sensor detects that the coolant temperature reaches the set value, the fan starts at a low speed according to the sensor signal. At this time, the diaphragm expansion tank is used to maintain the relative stability of the low pressure of the cooling circulation system.

[0027] When the line fault circuit breaker receives the disconnection command, it sends a signal to the water pump and fan at the same time, and the water pump and fan enter the high speed gear. At this time, the water tank is used to maintain the relative stability of the high pressure of the cooling circulation system.

[0028] As a further solution of the present invention, when the line fault circuit breaker receives a disconnection instruction, the fan blows air to the heat dissipation network to accelerate heat dissipation and at the same time, use the blowing to lengthen the circuit breaker arc and increase the circuit breaker impedance.

[0029] Beneficial effects of the present invention:

[0030] 1. The present invention provides a temperature sensor and a pressure sensor to send signals according to different temperatures to adjust the rotation speeds of the water pump and the fan. The cooling circulation system has a high degree of automation, which can avoid the fan and the water pump being in a high-power working state when the temperature is not high, thereby extending the service life of the equipment. At the same time, the cooling circulation system can meet the circuit breakers required by different temperature conditions and has a wide range of applications.

[0031] 2. When the pipeline pressure is low, the cooling circulation system of the present invention uses a diaphragm expansion tank to stabilize the pipeline pressure. The pressure fluctuation of the cooling circulation system is small, which can play a good buffering role, so that the pressure in the pipeline is maintained in a low-pressure range with a small variation range, and the cooling circulation system can be kept stable for a long time.

[0032] 3. When the pipeline is under high pressure, the cooling circulation system of the present invention can add water to the water tank for pressure adjustment, which can quickly reduce the coolant temperature and maintain the stable operation of the cooling circulation system when the pipeline is under high pressure, so that the pipeline pressure of the entire cooling circulation system can still be kept in a relatively stable state, better meet the operation requirements of the cooling circulation system, and avoid system pipeline bursting; at the same time, when the arc burning cannot be extinguished immediately, sufficient margin is left so that the coolant and the expanded gas are pressed into the water tank, preventing the cooling circulation system pressure from rising sharply and far exceeding the pressure relief rate and bursting, thereby improving the safety of system operation.

[0033] 4. The present invention reasonably sets the positions of the fan and the heat dissipation network so that the fan not only blows away the heat from the heat dissipation network, but also blows the arc in the circuit breaker, lengthens the arc discharge distance, increases its discharge distance, increases the circuit breaker impedance, helps to extinguish the arc, and can further prevent the cooling system from bursting due to excessive temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a schematic structural diagram of an automatic cooling circulation system and method for a high-voltage DC circuit breaker. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] like Figure 1 As shown, the present invention discloses a high-voltage DC circuit breaker automatic cooling circulation system and method, comprising:

[0037] The water jacket of the machine body is nested on the outside of the circuit breaker, and the heat generated by the circuit breaker is taken away by the circulation of coolant. A water pump is used to provide coolant circulation power. The coolant circulates and the heat dissipation area of ​​the coolant is increased by the heat dissipation network, so that the coolant and the air can exchange heat.

[0038] A fan is arranged outside the heat dissipation net to accelerate the heat dissipation of the heat dissipation net by blowing air from the fan. At the same time, when installing the fan, the use of its blowing effect on the arc of the circuit breaker should be considered. By setting an independent fan or adjusting the position of the heat dissipation net and the fan, the fan can be used to dissipate the heat of the heat dissipation net while blowing air to lengthen the arc of the circuit breaker, increase the arc discharge path of the circuit breaker, and then increase the impedance of the circuit breaker, which is conducive to the rapid extinction of the arc, thereby preventing the circuit breaker from overheating.

[0039] The diaphragm expansion tank is connected to the cooling circulation system. It can play a good buffering role for the low-pressure fluctuations of the cooling circulation system, so that the pressure in the pipeline is maintained in a low-pressure range with a small fluctuation range, so that the cooling circulation system can maintain long-term stable operation. The diaphragm expansion tank has good sealing performance, is not easy to leak water or air, has low maintenance costs, and has a high safety factor. At the same time, it can avoid leakage problems caused by damage to the bladder of an ordinary expansion tank.

[0040] When a diaphragm expansion tank is used, when the cooling circulation system is operating normally or the temperature changes, in order to solve the problem of low pressure instability, the diaphragm expansion tank is connected to an automatic exhaust valve. The automatic exhaust valve also acts as a safety valve to buffer pressure changes. Part of the gas pressure will be filled into the diaphragm expansion tank to convert the hydraulic pressure into elastic potential energy and store it in the tank, so that the water pump outlet can maintain a stable pressure. If there is a pressure fluctuation at the water pump outlet, the diaphragm expansion tank will automatically adjust the internal gas or store energy. If the system pressure is too high, the automatic exhaust valve will automatically discharge part of the gas to ensure that the system pressure remains normal and maintain a reasonable pressure for the system. The diaphragm expansion tank can absorb the volume changes of the cooling medium in the system due to thermal expansion and contraction, thereby ensuring long-term and stable operation of the entire system.

[0041] Furthermore, if Figure 1 As shown, the cooling circulation system also includes devices such as a pressure sensor, a temperature sensor, a water tank and a pressure valve.

[0042] Among them, the pressure sensor is used to measure the pressure in the cooling circulation system pipeline, the temperature sensor is used to measure the coolant temperature in the cooling circulation system pipeline, the water tank is connected to the cooling circulation system, and regulates the coolant in the cooling circulation system pipeline; the inlet and outlet of the water tank are connected to a pressure valve, and the pressure valve is opened and closed according to the pressure in the cooling circulation system pipeline to control the connection between the water tank and the cooling circulation system.

[0043] The water pump and the fan are electrically connected to the pressure sensor and the temperature sensor, and the water pump and the fan adjust the rotation speed according to the pressure sensor and the temperature sensor signals. Meanwhile, the water pump and the fan are electrically connected to the circuit breaker breaking command signal.

[0044] When the line is in normal operation, the water pump provides power to complete the water circulation between the circuit breaker water jacket and the heat dissipation network. At this time, the fan does not need to work to meet the circuit breaker's heat dissipation needs.

[0045] As the line operation time increases, the circuit breaker may generate heat accumulation due to overcurrent. When the temperature sensor detects that the temperature of the coolant in the cooling circulation system pipeline reaches the set value, it sends a signal to start the fan at low speed. As the temperature rises, the pipeline pressure is in a low-pressure fluctuating state. At this time, the diaphragm expansion tank can be used to maintain the relative stability of the cooling circulation system pressure. The cooling circulation system can maintain low-pressure stable operation, use the circulating flow of coolant to take away the heat generated by the circuit breaker, adjust the cold pipeline pressure, and maintain the cooling circulation system pipeline pressure stable.

[0046] When a line fault occurs, the circuit breaker receives a disconnection command signal and at the same time sends a signal to the water pump and fan to enter high gear, increasing the speed of water circulation and the speed of the fan. During the circuit breaker disconnection process, the temperature rise will be very fast, causing the coolant temperature to rise rapidly, and the pressure of the cooling circulation system to increase. At this time, relying solely on the diaphragm expansion tank is often unable to maintain the relative stability of the pressure of the cooling circulation system. At this time, the pressure valve will open, and the coolant and expansion gas will be discharged into the water tank. Through the fluid replenishment cycle, the coolant will flow back to the cooling circulation system to reduce the coolant temperature. The water tank is used to maintain the relative stability of the high pressure of the cooling circulation system. The pressure of the cooling circulation system pipeline can still remain in a relatively stable state, which can well meet the operation requirements of the cooling circulation system and avoid pipeline bursting.

[0047] Furthermore, through the reasonable setting of the fan and the heat dissipation network, when the line fault circuit breaker receives the disconnection command, the fan blows air to the heat dissipation network to accelerate the heat dissipation. At the same time, the air blowing is used to lengthen the circuit breaker arc, increase its discharge distance, increase the circuit breaker impedance, and speed up the arc extinguishing process, so that there is enough margin during the arc burning period, which can further prevent the cooling system from bursting due to excessive temperature.

[0048] Furthermore, the outlet and inlet of the water jacket of the machine body are connected with stop valves, which control the on-off of the pipeline. The inlet of the water tank is connected with a filter and a liquid replenishing valve. The valves are set to facilitate system maintenance.

[0049] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

Claims

1. A high voltage DC circuit breaker automatic cooling circulation system, characterized in that: include: The water jacket is nested outside the circuit breaker and removes the heat generated by the circuit breaker through the circulation of coolant; Water pump, providing coolant circulation power; Heat dissipation network: increase the heat dissipation area of ​​the coolant and perform heat exchange between the coolant and the air; The fan blows air to the heat dissipation net to speed up the heat dissipation, and at the same time uses the air to lengthen the circuit breaker arc and increase the circuit breaker impedance; The diaphragm expansion tank is connected to the cooling circulation system to adjust the pressure in the cooling circulation system pipeline.

2. The automatic cooling circulation system for a high-voltage DC circuit breaker according to claim 1, characterized in that: Also includes: Pressure sensor, measuring the pressure in the cooling circulation system pipeline; Temperature sensor, measuring the coolant temperature in the cooling circulation system pipeline; The water tank is connected to the cooling circulation system to regulate the coolant in the cooling circulation system pipeline; The pressure valve controls the connection between the water tank and the cooling circulation system according to the pressure in the cooling circulation system pipeline.

3. The automatic cooling circulation system for a high-voltage DC circuit breaker according to claim 1, characterized in that: The water pump and the fan are electrically connected to a pressure sensor and a temperature sensor, and the water pump and the fan adjust the rotation speed according to the pressure sensor and the temperature sensor signals.

4. The automatic cooling circulation system for a high-voltage DC circuit breaker according to claim 1, characterized in that: The water pump and the fan are electrically connected to a circuit breaker disconnection command signal.

5. The automatic cooling circulation system for a high-voltage DC circuit breaker according to claim 1, characterized in that: The diaphragm expansion tank is connected with an automatic exhaust valve.

6. The automatic cooling circulation system for a high-voltage DC circuit breaker according to claim 1, characterized in that: The outlet and the inlet of the water jacket of the machine body are connected with stop valves, and the stop valves control the on-off of the pipeline.

7. A high-voltage DC circuit breaker automatic cooling circulation method applied to the system according to any one of claims 1 to 6, characterized in that: include: The heat generated by the circuit breaker is removed by circulating coolant in the cooling circulation system, and the pressure of the cooling circulation system pipeline is adjusted by using a diaphragm expansion tank and / or a water tank to maintain a stable pressure in the cooling circulation system pipeline.

8. The method for automatic cooling cycle of a high-voltage DC circuit breaker according to claim 7, characterized in that: The method of regulating the cooling circulation system pipeline pressure comprises the following steps: When the circuit is working normally, the water pump provides coolant circulation power to complete the water circulation between the water jacket of the machine body and the heat dissipation network, and the fan does not work; When the temperature sensor detects that the coolant temperature reaches the set value, the fan starts at a low speed according to the sensor signal. At this time, the diaphragm expansion tank is used to maintain the relative stability of the low pressure of the cooling circulation system. When the line fault circuit breaker receives the disconnection command, it sends a signal to the water pump and fan at the same time, and the water pump and fan enter the high speed gear. At this time, the water tank is used to maintain the relative stability of the high pressure of the cooling circulation system.

9. The method for automatic cooling cycle of a high-voltage DC circuit breaker according to claim 7, characterized in that: When the line fault circuit breaker receives a disconnection command, the fan blows air to the heat dissipation network to speed up the heat dissipation, while using the air to lengthen the circuit breaker arc and increase the circuit breaker impedance.

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