Automatic inert gas adjusting system of ring main unit

Abstract

The utility model discloses an inert gas automatic adjusting system of a ring main unit. The inert gas automatic adjusting system comprises a power supply input part, a main circuit and a control circuit, the power supply input part comprises three-phase power supply inputs L1, L2 and L3, a zero line N and a three-phase circuit breaker QF; the main circuit comprises a gas pump driving motor M1 and a gas supplementing motor M2 which are respectively connected with a thermal relay FR1 and a thermal relay FR2; the control circuit comprises a start-stop control loop, a gas circulation control loop and a gas pressure adjusting loop; the start-stop control loop is used for controlling the system to start and stop; the gas circulation control loop is used for controlling the inert gas to circularly flow in the ring main unit; and the gas pressure adjusting loop is used for automatically supplementing or discharging gas according to the pressure of inert gas in the ring main unit. The inert gas automatic adjusting system of the ring main unit can automatically supplement or exhaust gas according to the pressure change, and realizes the circular flow of the gas through the gas pump, thereby improving the operation safety and stability of the ring main unit.

Description

Technical Field

[0001] The utility model relates to the field of power equipment, in particular to an inert gas automatic regulation system for a ring main unit. Background Art

[0002] The ring main unit is an important power distribution equipment in the urban power grid, mainly used for the distribution and control of electric energy, and plays an important role in the power system. Traditional ring main units generally use SF6 gas or inert gases such as dry air and nitrogen as insulating media, and the pressure state of these gases directly affects the insulation performance of the ring main unit and the normal operation of the switching equipment.

[0003] At present, the monitoring and regulation of gas pressure in the ring main unit mainly rely on the following methods: one is manual regular inspection, and the gas pressure is judged whether it is normal by reading the pressure gauge; the second is to set a simple pressure alarm device to send an alarm signal when the gas pressure is abnormal; the third is to install a mechanical pressure automatic gas replenishment system to automatically replenish gas when the air pressure drops to a certain value. These traditional methods have the following disadvantages:

[0004] The manual inspection cycle is long, and it is impossible to detect abnormal gas pressure in real time, which poses a safety hazard;

[0005] The mechanical automatic gas replenishment system has a complex structure, limited regulation accuracy, and can only solve the problem of reduced air pressure, and cannot handle the situation of too high air pressure;

[0006] The gas in the ring main unit is not flowing for a long time, which is easy to cause local overheating, affecting the equipment life and reliability;

[0007] The existing systems generally lack the gas circulation function and cannot effectively improve the internal temperature distribution of the ring main unit.

[0008] With the promotion of the construction of the smart grid, as a key power distribution equipment, the safety and reliability requirements of the ring main unit are getting higher and higher. Therefore, developing an intelligent system that can automatically monitor gas pressure, automatically regulate gas replenishment and discharge, and can achieve gas circulation is of great significance for improving the safety, reliability and service life of the ring main unit. Summary of the Utility Model

[0009] The purpose of the utility model is to provide an inert gas automatic regulation system for a ring main unit. This inert gas automatic regulation system for a ring main unit can automatically monitor the inert gas pressure in the ring main unit, automatically replenish or discharge gas according to the pressure change, and realize the gas circulation flow through the air pump, so as to improve the operation safety and stability of the ring main unit.

[0010] The above technical purpose of the utility model is achieved through the following technical solutions:

[0011] An inert gas automatic regulation system for a ring main unit, comprising: a power input section, a main circuit and a control circuit; the power input section includes three-phase power inputs L1, L2, L3 and a neutral line N, as well as a three-phase circuit breaker QF; the main circuit includes an air pump drive motor M1 and a gas replenishment motor M2, which are respectively connected with thermal relays FR1 and FR2; the control circuit includes a start-stop control loop, a gas circulation control loop and a gas pressure regulation loop; the start-stop control loop is used to control the start and stop of the system; the gas circulation control loop is used to control the circulation of inert gas in the ring main unit; the gas pressure regulation loop is used to automatically replenish or discharge gas according to the inert gas pressure in the ring main unit.

[0012] The present utility model is further arranged as: the start-stop control loop includes: a button SB1 and a start button SB2; the start button SB2 is connected with a control relay KA1; the control relay KA1 is provided with a self-locking contact for maintaining the continuous working state of the system.

[0013] The present utility model is further arranged as: the gas circulation control loop includes: a control relay KA1 contact, a relay KM1 and an air pump drive motor M1; after the control relay KA1 contact is closed, the relay KM1 is energized to control the start of the air pump drive motor M1 to drive the inert gas to circulate in the ring main unit.

[0014] The present utility model is further arranged as: the gas pressure regulation loop includes a low-pressure detection unit and a high-pressure detection unit; the low-pressure detection unit includes a low-pressure switch B1 with a threshold of P < 0.3 MPa, a relay KM2 and a gas replenishment motor M2; the high-pressure detection unit includes a high-pressure switch B2 with a threshold of P > 0.5 MPa and an exhaust valve EV.

[0015] The present utility model is further arranged as: the pressure threshold of the low-pressure switch B1 is set to 0.3 MPa. When the inert gas pressure in the ring main unit is lower than 0.3 MPa, the low-pressure switch B1 triggers the relay KM2 to close, and starts the gas replenishment motor M2 to replenish inert gas into the ring main unit.

[0016] The present utility model is further arranged as: the pressure threshold of the high-pressure switch B2 is set to 0.5 MPa. When the inert gas pressure in the ring main unit is higher than 0.5 MPa, the high-pressure switch B2 triggers the exhaust valve EV to open, and discharges part of the inert gas from the ring main unit.

[0017] The present utility model is further arranged as: the thermal relays FR1 and FR2 are respectively arranged in the power supply lines of the air pump drive motor M1 and the gas replenishment motor M2, and are used to cut off the power supply when the motor is overloaded to protect the safety of the motor.

[0018] The present utility model is further configured as follows: The system further includes contactors KM1-1 and KM2-1 in the main circuit, which are electrically connected to relays KM1 and KM2.

[0019] In summary, the present utility model has the following beneficial effects:

[0020] Fully automatic gas pressure regulation function: The system monitors the pressure of the inert gas in the ring main unit in real time through low-pressure switch B1 and high-pressure switch B2. When the pressure is lower than 0.3 MPa, gas is automatically supplemented; when the pressure is higher than 0.5 MPa, gas is automatically discharged, ensuring that the gas pressure is always maintained within a safe range without manual intervention, greatly improving the automation level and safety and reliability of the system. Specifically as follows:

[0021] 1. Gas circulation design: The system realizes the circulation of the inert gas in the ring main unit through the air pump driving motor M1, effectively improving the uniformity of gas distribution, preventing local overheating, enhancing the balance of the internal temperature of the ring main unit, and extending the service life of the equipment.

[0022] 2. Dual safety protection mechanism: The system is provided with thermal relays FR1 and FR2, which automatically cut off the power supply when the motor is overloaded to prevent motor damage; at the same time, a start-stop control circuit is provided, and the system power supply can be cut off at any time through the stop button to ensure the safe operation of the system.

[0023] 3. Pressure grading control strategy: The system adopts two pressure thresholds of 0.3 MPa and 0.5 MPa to form a grading control strategy of low-pressure supplementation and high-pressure discharge, avoiding frequent start-stop, reducing the system energy consumption, and improving the operation efficiency of the equipment.

[0024] 4. Self-locking design ensures continuous operation: The control relay KA1 is provided with a self-locking contact to ensure that the system can work continuously and stably after the start button is pressed. Even short-term voltage fluctuations will not affect the normal operation of the system, improving the stability of the system.

[0025] Compared with the prior art, the present system realizes an integrated design of gas pressure monitoring, automatic regulation, and circulation, solves the problems of the traditional gas management system for ring main units with single function, requiring manual intervention, and being unable to achieve gas circulation, and significantly improves the operation safety, reliability, and service life of the ring main unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the circuit schematic diagram of the inert gas automatic regulation system for the ring main unit of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In the description of the present utility model, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0029] In the description of the present utility model, the meaning of "a plurality of" is two or more, unless otherwise specifically defined. In the present utility model, unless otherwise clearly specified and defined, the terms such as "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0030] The present utility model will be further described in detail below with reference to the drawings.

[0031] As Figure 1 shown, the present utility model provides an inert gas automatic regulation system for a ring main unit, which mainly includes three parts: a power input part, a main circuit, and a control circuit.

[0032] The power input part includes three-phase power input lines L1, L2, and L3 and a neutral line N, which are connected to the system through a three-phase circuit breaker QF to provide power support for the entire system. The three-phase circuit breaker QF functions as a main switch and short-circuit protection to ensure the electrical safety of the system.

[0033] The main circuit mainly includes the air pump drive motor M1 and the gas replenishment motor M2. Among them, the motor M1 is responsible for driving the air pump to make the inert gas in the ring main unit circulate, playing the role of balancing the gas distribution and improving the heat dissipation effect; the gas replenishment motor M2 is responsible for driving the air pump to replenish the inert gas into the ring main unit when the gas pressure is insufficient. Thermal relays FR1 and FR2 are also set in the main circuit, which are connected in series with the air pump drive motor M1 and the gas replenishment motor M2 respectively, and are used to monitor the operating current of the motors. When the motors are overloaded, the circuit is automatically disconnected to protect the motors from damage.

[0034] The control circuit is divided into three main functional loops: the start-stop control loop, the gas circulation control loop, and the gas pressure regulation loop.

[0035] The start-stop control loop includes the button SB1, the start button SB2, and the control relay KA1. After pressing the start button SB2, the control relay KA1 is powered on, and at the same time, the self-locking contact of KA1 closes, maintaining the powered-on state of the control relay KA1 and enabling the system to continue working. Pressing the button SB1 cuts off the power supply of the control relay KA1, and the system stops working. Through the above settings, the system can run continuously and stably after one start until the button SB1 is actively pressed or a fault protection occurs.

[0036] The gas circulation control loop includes the contact of the control relay KA1, the relay KM1, and the air pump drive motor M1. When the control relay KA1 is powered on, its contact closes, the relay KM1 is powered on, and the power supply of the air pump drive motor M1 is connected, and M1 starts to run, driving the air pump to make the inert gas in the ring main unit circulate. This circular flow helps to balance the internal temperature of the ring main unit, avoid local overheating, and improve the safety and service life of the equipment.

[0037] The gas pressure regulation loop includes a low-pressure detection unit and a high-pressure detection unit. The low-pressure detection unit consists of a low-pressure switch B1 (P < 0.3 MPa), a relay KM2, and the gas replenishment motor M2.

[0038] When the pressure of the inert gas in the ring main unit is lower than 0.3 MPa, the low-pressure switch B1 closes, causing the relay KM2 to be powered on, connecting the power supply of the gas replenishment motor M2, and M2 starts to run in the forward direction to replenish the inert gas into the ring main unit until the pressure returns to the safe range. The high-pressure detection unit consists of a high-pressure switch B2 (P > 0.5 MPa) and a relay KM3. When the pressure of the inert gas in the ring main unit is higher than 0.5 MPa, the high-pressure switch B2 closes to open the exhaust valve EV, discharging some of the inert gas from the ring main unit to avoid damage to the equipment caused by excessive pressure.

[0039] The system also includes contactors KM1-1 and KM2-1 in the main circuit, which are electrically connected to relays KM1 and KM2 and are controlled by relays KM1 and KM2 to be turned on and off. Through this setting, the control circuit is separated from high-power equipment, improving the safety and reliability of the system.

[0040] The working principle is as follows:

[0041] System startup: After the power is turned on, press the start button SB2, the control relay KA1 is energized and self-locked, and the system enters the working state.

[0042] Gas circulation: After the control relay KA1 is energized, through its contacts, the relay KM1 is energized, the contactor KM1-1 closes, the air pump drive motor M1 starts to run, driving the air pump to make the inert gas in the ring main unit circulate, balancing the gas distribution and improving the heat dissipation effect.

[0043] Low-pressure automatic gas replenishment: The system continuously monitors the pressure of the inert gas in the ring main unit. When the pressure is lower than 0.3 MPa, the low-pressure switch B1 closes, causing the contactor KM2-1 to close, and the gas replenishment motor M2 starts to run, replenishing the inert gas into the ring main unit until the pressure rises back to the safe range.

[0044] High-pressure automatic exhaust: When the pressure of the inert gas in the ring main unit is higher than 0.5 MPa, the high-pressure switch B2 closes, causing the exhaust valve EV to open, discharging some of the inert gas from the ring main unit until the pressure drops to the safe range.

[0045] Overload protection: Thermal relays FR1 and FR2 respectively monitor the operating currents of the air pump drive motor M1 and the gas replenishment motor M2. When the motor current exceeds the set value, the thermal relay operates, cutting off the power supply of the corresponding motor to prevent the motor from being damaged due to overload.

[0046] System stop: Press the button SB1, cut off the power supply of the control relay KA1, KA1 loses power, its contacts open, and relays KM1 and KM2 both lose power, and the system stops working.

[0047] The automatic inert gas regulation system for the ring main unit of the present utility model realizes functions such as automatic monitoring and regulation of the inert gas pressure, automatic control of gas circulation, and motor overload protection through an electrical control method. It has the characteristics of simple structure, convenient operation, safety and reliability, etc., can effectively improve the operating safety and service life of the ring main unit, and has a wide range of application prospects.

[0048] This specific embodiment is only an explanation of the present utility model, and it is not a limitation of the present utility model. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as it is within the scope of the claims of the present utility model, it is protected by the patent law.

Claims

1. An inert gas automatic regulation system for a ring main unit, characterized in that It includes: a power input section, a main circuit, and a control circuit; the power input section includes three-phase power inputs L1, L2, L3 and a neutral line N, as well as a three-phase circuit breaker QF; the main circuit includes an air pump drive motor M1 and a gas replenishment motor M2, which are respectively connected with thermal relays FR1 and FR2; the control circuit includes a start-stop control loop, a gas circulation control loop, and a gas pressure regulation loop; the start-stop control loop is used to control the start and stop of the system; the gas circulation control loop is used to control the circulation of inert gas in the ring main unit; the gas pressure regulation loop is used to automatically replenish or discharge gas according to the inert gas pressure in the ring main unit.

2. The inert gas automatic regulation system of the ring main unit according to claim 1, characterized in that: The start-stop control loop includes: a button SB1 and a start button SB2; the start button SB2 is connected with a control relay KA1; the control relay KA1 is provided with a self-locking contact for maintaining the continuous working state of the system.

3. The inert gas automatic regulation system of the ring main unit according to claim 2, characterized in that: The gas circulation control loop includes: a control relay KA1 contact, a relay KM1, and an air pump drive motor M1; after the control relay KA1 contact is closed, the relay KM1 is powered on to control the start of the air pump drive motor M1 to drive the inert gas to circulate in the ring main unit.

4. The inert gas automatic regulation system of the ring main unit according to claim 1, characterized in that: The gas pressure regulation loop includes a low-pressure detection unit and a high-pressure detection unit; the low-pressure detection unit includes a low-pressure switch B1 with a threshold of P < 0.3 MPa, a relay KM2, and a gas replenishment motor M2; the high-pressure detection unit includes a high-pressure switch B2 with a threshold of P > 0.5 MPa and an exhaust valve EV.

5. The inert gas automatic regulation system of the ring main unit according to claim 4, characterized in that: The pressure threshold of the low-pressure switch B1 is set to 0.3 MPa. When the inert gas pressure in the ring main unit is lower than 0.3 MPa, the low-pressure switch B1 triggers the relay KM2 to close, starting the gas replenishment motor M2 to replenish inert gas into the ring main unit.

6. The inert gas automatic regulation system of the ring main unit according to claim 4, characterized in that: The pressure threshold of the high-pressure switch B2 is set to 0.5 MPa. When the inert gas pressure in the ring main unit is higher than 0.5 MPa, the high-pressure switch B2 triggers the exhaust valve EV to open, discharging part of the inert gas from the ring main unit.

7. The inert gas automatic regulation system of the ring main unit according to claim 1, characterized in that: The thermal relays FR1 and FR2 are respectively arranged in the power supply lines of the air pump drive motor M1 and the gas replenishment motor M2, and are used to cut off the power supply when the motor is overloaded to protect the safety of the motor.

8. The inert gas automatic regulation system of the ring main unit according to claim 1, characterized in that: The system also includes contactors KM1-1 and KM2-1 in the main circuit, which are electrically connected with relays KM1 and KM2.

Images