Coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system and method

Abstract

The application relates to the technical field of coal mine safety power supply, and discloses a coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system and method, which comprises a circuit breaker, a control transformer, a rectifier bridge and an energy storage control module; the method comprises the following steps: detecting the voltage in real time and inputting the control module to determine whether the charging or power supply condition is met; when the voltage is higher than the set value, the charging is started, and when the voltage is lower than the set value, the power supply is switched and timing is performed; the coil attraction is maintained in the power supply state, the recovery is charged, and the timeout is disconnected; the circuit breaker is tripped after the power supply is cut off; the discharge circuit one is started to release residual energy, the alternating current compensation voltage is output during the energy storage inversion, the discharge circuit two releases residual energy after the power supply is cut off, and voltage dynamic regulation is realized through inversion output. According to the application, the energy storage backup power source with monitoring and switching control capacity is introduced at both ends of the loss-of-voltage release coil, the system automatically delays the power supply after identifying the short-time voltage drop, and the tripping triggered by the pressure drop is prevented.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of coal mine safety power supply, in particular to a coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system and method. BACKGROUND

[0002] The underground power supply system of a coal mine generally adopts a multi-stage distributed feeder structure. Due to the special environment, dense equipment, long power supply line and susceptibility to interference, the system has extremely high requirements for power supply continuity and voltage stability. Especially in electrical devices related to personnel safety and key production processes, once the power supply is interrupted, the equipment will be shut down, or even a safety accident will be caused. In order to ensure that the power supply can be quickly cut off under abnormal conditions and prevent the extension of live faults, most feeder switches are provided with a loss-of-voltage release protection device.

[0003] Most existing loss-of-voltage release devices adopt an electromagnetic attraction structure directly powered by a rectifier bridge. Once the voltage is lower than the set attraction value, the coil loses power, the release actuator operates, and the circuit breaker immediately trips. This type of device has simple structure and fast response, and is widely deployed in electrical protection scenes such as coal mines and tunnels. Some systems adjust the control transformer capacity or optimize the line matching to improve the stability of the rectifier output, but still belong to the instant power supply interruption strategy.

[0004] However, the loss-of-voltage release device widely used in the existing coal mine low-voltage feeder system mainly relies on an electromagnetic-mechanical structure to realize power-off action, and its working state is directly controlled by the coil voltage, lacking a logic judgment and delay tolerance mechanism for voltage state. In the system operation process, this type of structure cannot distinguish between transient voltage fluctuation and real loss-of-voltage event, neither has the ability to judge the dynamic voltage trend nor is configured with a delay tripping function. Therefore, the coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system and method are provided to solve the problems in the prior art. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system and method, which solves the problems that the loss-of-voltage release device in the coal mine low-voltage feeder system relies on an electromagnetic-mechanical structure, cannot distinguish between short-time voltage disturbance and real loss-of-voltage state, lacks a delay fault tolerance mechanism and is prone to false tripping.

[0006] To achieve the above purpose, the present application is implemented by the following technical scheme: a coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system, comprising:

[0007] A circuit breaker is arranged in the main power supply circuit of the coal mine low-voltage feeder system and is used as a main control opening unit of the power supply system to control the transmission and interruption of electric energy of the entire line through the closed state.

[0008] A control transformer, a primary side of the control transformer is connected to a load side three-phase main line of the circuit breaker, and is used to obtain power from a main power system in a closed state of the circuit breaker, and output a stable low-voltage control voltage signal through a secondary side of the control transformer;

[0009] A rectifier bridge, an input end of the rectifier bridge is connected to the output end of the secondary side of the control transformer, and an under-voltage release coil is arranged at an output end of the rectifier bridge, and the under-voltage release coil is maintained in an energized attraction state by a direct-current voltage output by the rectifier bridge;

[0010] An energy storage control module, the energy storage control module comprises an energy storage backup power supply or an inverter energy storage power supply, and is used to provide a delay power supply when a control voltage or a main voltage fluctuates for a short time, to maintain the closed state of the circuit breaker, to prevent the under-voltage release coil from being tripped by mistake due to a transient voltage drop, and to cut off the energy storage power supply under a continuous under-voltage condition, so as to cause the circuit breaker to trip.

[0011] Preferably, the energy storage backup power supply comprises:

[0012] A voltage measurement circuit one, an input end of the voltage measurement circuit one is connected to the output end of the rectifier bridge, and is used to collect a direct-current voltage signal in a feeder switch control circuit in real time, and to determine a current power supply state;

[0013] A control circuit one, the control circuit one is electrically connected to the voltage measurement circuit one, and is used to control a charging or power supply operation according to a result of determining the current power supply state;

[0014] An energy storage circuit one, the energy storage circuit one is electrically connected to the control circuit one, one end of the energy storage circuit one is connected to the output end of the rectifier bridge, and is used to receive power and store energy in a charging state, and the other end of the energy storage circuit one is connected to the under-voltage release coil, and is used to output a holding voltage in a power supply state, to maintain an attraction state of the under-voltage release coil;

[0015] An energy storage measurement circuit one, the energy storage measurement circuit one is connected to the energy storage circuit one, and is used to monitor an energy storage voltage, an energy amount or a remaining power supply capacity, and to feed back monitored data to the control circuit one;

[0016] A discharge circuit one, the discharge circuit one is connected between the energy storage circuit one and the control circuit one, and is used to safely release energy storage charges according to an instruction output by the control circuit one after a power supply system completes tripping or cutting off power supply.

[0017] Preferably, the control circuit one comprises:

[0018] A charging voltage control constant value unit, the charging voltage control constant value unit is used to determine whether the output voltage of the rectifier bridge is higher than a preset charging voltage control voltage constant value, to control the energy storage circuit one to enter the charging state;

[0019] A power supply voltage control setting unit is configured to determine whether the output voltage of the rectifier bridge is lower than a preset power supply voltage control voltage setting value, and to control the energy storage circuit to switch to a power supply state;

[0020] A power supply time counting unit is configured to start counting when the energy storage backup power supply is in the power supply state, and to switch to a charging state if the output voltage of the rectifier bridge is restored to above the charging voltage control setting value within a preset power supply time setting value, and to control the energy storage output to be cut off and trigger the loss-of-voltage release coil to trip if the counting setting value is exceeded.

[0021] Preferably, the discharge circuit is configured to automatically turn on to release the residual energy in the energy storage circuit one after the control circuit cuts off the power supply output.

[0022] Preferably, the inverter energy storage power supply comprises:

[0023] A voltage measurement circuit two is connected to the main circuit, configured to detect the voltage of the main circuit in real time and collect voltage signals;

[0024] A control circuit two is electrically connected to the voltage measurement circuit two, configured to perform logical determination based on the voltage measurement signals, the set charging voltage control setting value, the power supply voltage control setting value and the power supply time setting value, and to control the inverter energy storage power supply to switch between the charging state, the power supply state and the power supply cut-off state;

[0025] An energy storage circuit two is electrically connected to the control circuit two, configured to receive the power supply energy of the main circuit and store the energy in the charging state, and to provide the energy storage power in the power supply state;

[0026] An inverter circuit is connected in parallel to the energy storage circuit two and the main circuit, configured to invert the energy storage power into an alternating voltage synchronized with the main circuit to provide stable power supply to the feeder switch and the main line load, and to maintain the attraction voltage for the loss-of-voltage release coil in the power supply state;

[0027] An energy storage measurement circuit two is connected to the energy storage circuit two, configured to detect the voltage, the power or the residual energy storage capacity of the energy storage unit in real time, and to feed back the detection results to the control circuit two for power supply feasibility determination by the control circuit;

[0028] A discharge circuit two is connected to the control circuit two and the energy storage circuit two, configured to automatically turn on to release the residual energy in the energy storage circuit after the control circuit two issues a power cut-off instruction.

[0029] Preferably, the inverter circuit synchronously tracks the voltage frequency and phase of the main circuit in the power supply state, adjusts the output waveform in real time, and compensates for the dynamic voltage during the short-term fluctuation of the main circuit voltage.

[0030] Preferably, the inverter circuit and the energy storage circuit together have a harmonic absorption function, and when there are peak voltage or high frequency harmonic components in the main circuit, the voltage peak and harmonic fluctuation are automatically suppressed through inverter adjustment and energy storage absorption.

[0031] Preferably, the control circuit two is used to control the inverter circuit to output dynamic compensation voltage in real time during the short-time fluctuation of the power supply voltage, so as to maintain the normal operation of the feeder switch and the main circuit load.

[0032] A coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping method is also provided, which comprises the following steps:

[0033] The voltage of the main circuit or the control circuit is detected in real time by controlling the transformer and the rectifier bridge, and the obtained voltage signal is input to the energy storage control module;

[0034] The control circuit in the energy storage control module determines whether the current voltage state meets the preset condition of the charging state or the power supply state according to the voltage measurement result;

[0035] When the voltage is greater than the charging voltage control constant, the energy storage circuit enters the charging state and stores electric energy, and when the voltage is lower than the power supply voltage control constant, the power supply state is switched to and the timing is started;

[0036] In the power supply state, a stable voltage is provided for the loss-of-voltage release coil to maintain its attraction state, so as to keep the circuit breaker closed for power supply. If the voltage recovers to above the charging voltage control constant within the power supply time constant, the charging state is switched to again, and if the voltage does not recover within the set power supply time, the power supply output is controlled to be cut off;

[0037] After the power supply is cut off, the loss-of-voltage release coil loses power, drives the circuit breaker to trip, and cuts off the main circuit, thereby realizing the time-delay tripping function;

[0038] After the power supply is cut off, the discharge circuit one is started to release the residual electric energy in the energy storage circuit one, thereby ensuring the safety of the system and personnel;

[0039] When the inverter energy storage power supply is adopted, the inverter circuit converts the energy storage electric energy into alternating voltage in the power supply state, provides dynamic voltage compensation for the main load, and suppresses the power grid fluctuation and harmonic interference;

[0040] After the power supply is cut off, the discharge circuit two is started to release the residual electric energy in the energy storage circuit two, thereby ensuring the safety of the system and personnel;

[0041] When the inverter energy storage power supply is adopted, the inverter circuit converts the energy storage electric energy into alternating voltage in the power supply state, provides dynamic voltage compensation for the main load, and suppresses the power grid fluctuation and harmonic interference.

[0042] In summary, the present application has at least one of the following beneficial technical effects:

[0043] 1. The present application avoids the rigid response logic of traditional feeder switches that immediately trip under transient fluctuations by introducing an energy storage backup power source with monitoring and switching control capabilities at both ends of the loss-of-voltage release coil. The system automatically delays power supply after identifying a temporary voltage drop, preventing the triggering of a trip as soon as the voltage drops. It is especially suitable for complex mine power supply environments with lightning strikes, flicker, and short circuit disturbances, effectively reducing the probability of false shutdown.

[0044] 2. The inverter energy storage module constructed in the present application can output AC voltage synchronized with the main power grid in a power loss state, achieving dynamic voltage compensation and power supply continuity for the main load. This structure breaks through the single-point support mode of traditional feeder protection, which only maintains the attraction of the release, and has the functions of power supply and voltage regulation, significantly improving the voltage quality control capability during system operation and reducing the risk of load fluctuation and energy consumption rise caused by transient drop.

[0045] 3. The energy storage system is equipped with an automatic discharge circuit, which can actively release residual charge after power failure, ensuring that there is no residual voltage left in the system in the open state. Compared with the existing technology, this scheme significantly improves the static electrical safety level of the equipment in an explosion-proof environment, and solves the problems of incomplete energy storage release and induced electric risk during maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is the schematic diagram of the energy storage backup power source of the present application;

[0047] Figure 2 is the architecture diagram of the energy storage backup power source of the present application;

[0048] Figure 3 is the schematic diagram of the inverter energy storage power source of the present application;

[0049] Figure 4 is the architecture diagram of the inverter energy storage power source of the present application;

[0050] Figure 5 is the method step flow chart of the present application.

[0051] 1, circuit breaker; 2, control transformer; 3, rectifier bridge; 4, loss-of-voltage release coil; 5, energy storage backup power source; 6, voltage measurement circuit one; 7, control circuit one; 8, energy storage circuit one; 9, energy storage measurement circuit one; 10, discharge circuit one; 11, inverter energy storage power source; 12, voltage measurement circuit two; 13, control circuit two; 14, energy storage circuit two; 15, inverter circuit; 16, energy storage measurement circuit two; 17, discharge circuit two. DETAILED DESCRIPTION

[0052] The following will be described in conjunction with the accompanying Figure 1 - the accompanying Figure 5Further details of the application are provided below.

[0053] Embodiment one:

[0054] Please refer to the attached Figure 1 and attached Figure 2 The coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system provided by the embodiment of the application is suitable for important power supply branches in the scene of power grid disturbance and short-time voltage fluctuation in coal mine underground. The system takes the energy storage backup power supply 5 as the core, has the functions of voltage loss monitoring, charging and discharging control, automatic delay tripping and discharge protection, and realizes stable power supply control of the voltage loss tripping device of the feeder switch.

[0055] The main power supply line of the low-voltage feeder switch is controlled by the circuit breaker 1 to control the on-off of electric energy; the load side three-phase main line of the circuit breaker 1 is connected to the primary side of the control transformer 2, and the control transformer 2 is used to obtain alternating current energy from the main power system and output a stable low-voltage control voltage signal on the secondary side. The alternating current output on the secondary side of the control transformer 2 is rectified into direct current voltage by the rectifier bridge 3, and then supplies power to the voltage loss tripping coil 4 to maintain it in the attracted state, so as to realize the closing operation of the circuit breaker 1.

[0056] In order to avoid the tripping coil from being tripped due to short-time voltage fluctuation of the power supply, an energy storage backup power supply 5 is connected between the output end of the rectifier bridge 3 and the voltage loss tripping coil 4. The energy storage backup power supply 5 comprises:

[0057] The voltage measurement circuit one 6 is connected to the output end of the rectifier bridge 3, and is used to collect direct current voltage in the feeder switch control circuit in real time and judge whether the current voltage is within the set threshold range;

[0058] The control circuit one 7 is electrically connected with the voltage measurement circuit one 6, and is used to control the charging or power supply switching of the energy storage circuit one 8 based on the voltage state, and has the functions of power supply time counting and power supply cutting-off logical judgment;

[0059] The energy storage circuit one 8 is connected between the rectifier bridge 3 and the voltage loss tripping coil 4, and is used to receive and store electric energy in normal power supply, and provide direct current holding voltage when the voltage is lower than the set power supply voltage value, so as to ensure that the voltage loss tripping device is not attracted and tripped;

[0060] The energy storage measurement circuit one 9 is used to detect the voltage, electric quantity and residual power supply capacity of the energy storage unit in real time, and feed back the data to the control circuit one 7 to assist decision-making;

[0061] The discharge circuit one 10 is used to automatically start to release the residual charge in the energy storage circuit one 8 to a safe state after the control circuit one 7 cuts off the power supply output, so as to ensure the safety of maintenance and explosion-proof compliance.

[0062] During operation, when the output voltage of the rectifier bridge 3 is higher than the preset charging voltage control constant value, the control circuit 7 controls the energy storage circuit 8 to enter the charging state, and directly charges the energy storage circuit 8 from the rectifier bridge 3, so that the energy storage circuit 8 is in an energy storage state at any time.

[0063] When the main power voltage fluctuates due to lightning, flicker, load mutation and other factors, the output voltage of the rectifier bridge 3 synchronously decreases and is lower than the supply voltage control constant value, the control circuit 7 immediately switches the energy storage circuit 8 to the power supply state, and simultaneously starts the power supply time counting. At this time, the output voltage of the energy storage circuit 8 is maintained, and the loss voltage release coil 4 is provided with stable DC power to maintain the attraction state, thereby preventing the circuit breaker 1 from tripping.

[0064] If the voltage of the rectifier bridge 3 recovers to be higher than the charging control constant value within the power supply time constant value set in the power supply time counting unit, the control circuit 7 immediately switches the energy storage backup power supply 5 to the charging state, and terminates the power supply output, so that the release device is maintained by the rectifier bridge 3.

[0065] If the voltage fails to recover within the power supply time constant value, the control circuit 7 controls the energy storage circuit 8 to cut off the power supply after the timing is cut off, the loss voltage release coil 4 loses power, the release device acts to make the circuit breaker 1 trip, and the “delayed tripping” function is realized. The delay mechanism effectively avoids the false tripping phenomenon caused by short-time recoverable voltage fluctuation.

[0066] After the power supply is cut off, the control circuit 7 outputs an instruction to turn on the discharge circuit 10, so that the residual energy in the energy storage circuit 8 is released in a safe manner, the risk of electric shock and loss of explosion in the subsequent maintenance process is prevented, and the electrical safety of the coal mine explosion-proof area equipment is ensured.

[0067] Embodiment two:

[0068] Please refer to the accompanying Figure 3 and the accompanying Figure 4 , the coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system provided by the embodiment of the present application can maintain the stable closing of the feeder switch and provide dynamic voltage compensation for the load during the voltage fluctuation of the power grid, effectively prevents the tripping power failure accident caused by instantaneous loss of voltage, and is particularly suitable for the mine environment with high load continuity requirement.

[0069] In the embodiment, the circuit breaker 1 arranged on the main circuit of the coal mine low-voltage feeder is used to control the on-off of the main circuit. The three-phase main power supply line at the front end of the circuit breaker 1 is branched to the primary side of the control transformer 2, the control transformer 2 outputs stable low-voltage alternating control voltage, the rectifier bridge 3 rectifies the output direct current voltage, and the control system, the protection module and the loss voltage release coil 4 of the feeder switch are provided with working voltage, so that the normal closing operation of the circuit breaker 1 is maintained.

[0070] To enhance the system's ability to resist voltage disturbance, an inverter energy storage power supply 11 is connected in parallel on the main circuit. The inverter energy storage power supply 11 has functions such as charge state switching, power supply state switching, power-off delay tripping, dynamic voltage compensation, and automatic discharge protection, and is mainly composed of the following units:

[0071] The voltage measurement circuit two 12 is directly connected to the input of the main circuit, used to monitor the voltage level of the main circuit in real time, and generate corresponding voltage sampling signals;

[0072] The control circuit two 13 is electrically connected with the voltage measurement circuit two 12, used to make logical judgments based on the sampling voltage and the preset charge control voltage, power supply control voltage, and power supply time value, to control the system state to switch between charging, power supply, and power supply interruption;

[0073] The energy storage circuit two 14 receives and stores energy when the main circuit voltage is normal, and outputs energy storage energy to provide maintenance power supply for the main load and the loss of voltage release coil 4 when the main voltage is lower than the power supply value;

[0074] The inverter circuit 15 is connected in parallel with the energy storage circuit two 14 and the main circuit, used to invert the direct current energy storage power into an alternating current voltage synchronized with the main circuit, dynamically compensate the power supply when the power grid fluctuates, and ensure the continuous operation of the main load;

[0075] The energy storage measurement circuit two 16 is used to detect the energy storage voltage, power, and residual discharge capacity, and feed back the monitoring results to the control circuit two 13 to assist it in making power supply decisions;

[0076] The discharge circuit two 17 is automatically connected after the energy storage power supply is cut off, to release the residual energy in the energy storage circuit, and ensure electrical safety in the coal mine explosion-proof environment.

[0077] When the main circuit voltage is higher than the preset charge control voltage value, the control circuit two 13 controls the inverter energy storage power supply 11 to be in the charging state, and the main line charges the energy storage circuit two 14 to maintain its energy storage saturation state.

[0078] When the power grid voltage fluctuates due to lightning, short circuit, impact load, etc., causing the main circuit voltage to drop below the power supply control voltage value, the control circuit two 13 immediately controls the system to switch to the power supply state, and starts the power supply timer. The energy storage circuit two 14 begins to provide power to the main circuit and the loss of voltage release coil 4, and the inverter circuit 15 converts the energy storage voltage into an alternating current form and synchronizes the main circuit frequency and phase, to ensure that the feeder switch does not trip and the main line load is not powered off.

[0079] If the main circuit voltage recovers to be higher than the charge control voltage value within the power supply time value, the control circuit two 13 controls the inverter energy storage power supply 11 to switch back to the charging state, and the power grid resumes to bear the load power supply.

[0080] If the voltage does not recover within the supply time, it is judged as a real voltage loss, the control circuit 13 performs the supply interruption operation, stops the inverter power supply, the loss voltage release coil 4 loses power, the release acts to push the circuit breaker 1 to trip, and the delay trip protection is realized.

[0081] In addition, in order to ensure the safety of the system after maintenance, shutdown or abnormal power failure, the control circuit 13 controls the discharge circuit 17 to be turned on after the supply interruption instruction is issued, and the residual energy in the energy storage circuit is released, so as to prevent the risk of electric shock or the danger of loss of explosion caused by residual energy, and ensure the electrical safety of the whole system in the explosion-proof coal mine environment.

[0082] Specifically, the inverter circuit 15 can also absorb the peak voltage and high frequency harmonic through the energy provided by the energy storage circuit 14, realize harmonic absorption and power quality optimization, effectively reduce the impact and loss caused by harmonic fluctuation on sensitive equipment, and improve the overall stability and service life of the system.

[0083] The coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping method described below can be correspondingly referred to the coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system described above.

[0084] Please refer to the accompanying Figure 5 The application also provides a coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping method, comprising the following steps:

[0085] The voltage of the main circuit or the control circuit is detected in real time by controlling the transformer 2 and the rectifier bridge 3, and the obtained voltage signal is input to the energy storage control module;

[0086] The control circuit in the energy storage control module judges whether the current voltage state meets the preset condition of the charging state or the switching to the power supply state according to the voltage measurement result;

[0087] When the voltage is greater than the charging voltage control constant, the energy storage circuit enters the charging state and stores energy, and when the voltage is lower than the power supply voltage control constant, it is switched to the power supply state and starts timing;

[0088] In the power supply state, a stable voltage is provided for the loss voltage release coil 4 to maintain its attraction state, keep the circuit breaker 1 closed for power supply, if the voltage recovers to above the charging voltage control constant within the supply time constant, it is switched to the charging state again, if it still does not recover after the set supply time, the control is cut off;

[0089] After the power supply is cut off, the loss voltage release coil 4 loses power, drives the circuit breaker 1 to trip, cuts off the main circuit, and realizes the delay trip function;

[0090] The discharge circuit 10 is started after power supply is cut off, residual energy in the energy storage circuit 8 is released, and system and personnel safety is ensured.

[0091] When the inverter energy storage power supply 11 is adopted, the inverter circuit 15 converts the energy storage electricity into alternating voltage in the power supply state, provides dynamic voltage compensation for the main load, and suppresses power grid fluctuation and harmonic interference.

[0092] The discharge circuit 17 is started after power supply is cut off, residual energy in the energy storage circuit 14 is released, and system and personnel safety is ensured.

[0093] When the inverter energy storage power supply 11 is adopted, the inverter circuit 15 converts the energy storage electricity into alternating voltage in the power supply state, provides dynamic voltage compensation for the main load, and suppresses power grid fluctuation and harmonic interference.

[0094] The method of the embodiment can be used to execute the above-mentioned system embodiment, and the principle and technical effects are similar, and will not be described here.

[0095] The embodiments of the specific implementation are the preferred embodiments of the application, and are not limited to the protection scope of the application, wherein the same parts are denoted by the same reference numerals. Therefore, equivalent changes made according to the structure, shape, principle of the application should be covered in the protection scope of the application.

Claims

1. A coal mine low-voltage feeder switch voltage short-time fluctuation anti-tripping system, characterized in that, The application relates to a low-voltage feeder circuit breaker for a coal mine, which comprises the following components: a circuit breaker (1) arranged in a main power supply circuit of a low-voltage feeder system of a coal mine, used as a main control and breaking unit of the power supply system, and capable of controlling the transmission and interruption of electric energy of the whole line through a closed state; a control transformer (2) whose primary side is connected to a three-phase main line on the load side of the circuit breaker (1), used for inductively obtaining electric energy from a main power system in the closed state of the circuit breaker (1), and outputting a stable low-voltage control voltage signal through a secondary side of the control transformer (2); a rectifier bridge (3) whose input end is connected to the output of the secondary side of the control transformer (2), and whose output end is provided with a loss-of-voltage release coil (4) which is maintained in an energized attraction state by the direct-current voltage stably output by the rectifier bridge (3); an energy storage control module comprising an energy storage backup power supply (5) or an inverter energy storage power supply (11), used for providing delay power supply when the control voltage or the main voltage fluctuates for a short time, maintaining the closed state of the circuit breaker (1), preventing the loss-of-voltage release coil (4) from being tripped due to instantaneous voltage drop, and cutting off the energy storage power supply under the condition of continuous loss of voltage to make the circuit breaker (1) trip; the inverter energy storage power supply (11) comprises: a voltage measurement circuit (12) whose input end is connected to a main circuit, used for detecting the voltage of the main circuit in real time and collecting a voltage signal; a control circuit (13) electrically connected to the voltage measurement circuit (12), used for performing logical judgment based on the voltage measurement signal, a set charging voltage control constant value, a power supply voltage control constant value and a power supply time constant value, and controlling the inverter energy storage power supply (11) to switch between a charging state, a power supply state and a power supply interruption state; an energy storage circuit (14) electrically connected to the control circuit (13), used for receiving power supply energy of the main circuit and storing in the charging state, and providing energy storage electric energy in the power supply state; an inverter circuit (15) connected in parallel with the energy storage circuit (14) and the main circuit, used for inverting the energy storage electric energy into an alternating voltage synchronous with the main circuit in the power supply state, providing a stable power supply to a feeder switch and a main line load, and maintaining an attraction voltage for the loss-of-voltage release coil (4); an energy storage measurement circuit (16) connected to the energy storage circuit (14), used for detecting the voltage, the electric quantity or the residual energy storage capacity of the energy storage unit in real time, and feeding back the detection result to the control circuit (13) for power supply feasibility judgment of the control circuit; a discharge circuit (17) connected to the control circuit (13) and the energy storage circuit (14), used for being automatically turned on after the control circuit (13) issues a power supply interruption instruction, and releasing residual electric energy in the energy storage circuit; the inverter circuit (15) synchronously tracks the voltage frequency and phase of the main circuit in the power supply state, adjusts an output waveform in real time, and compensates for a dynamic voltage during a short-time fluctuation of the main circuit voltage. The control circuit two (13) is used for controlling the inverter circuit (15) to output dynamic compensation voltage in real time during short-time fluctuation of power supply voltage, so as to keep the normal operation of the feeder switch and the main circuit load.

2. The low-voltage power supply switch voltage short-time fluctuation anti-tripping system for coal mines according to claim 1, characterized in that, The inverter circuit (15) and the energy storage circuit two (14) have harmonic absorption function together, and when there is a peak voltage or a high-frequency harmonic component in the main circuit, the voltage peak and the harmonic fluctuation are automatically inhibited by the inverter adjustment and the energy storage absorption.

3. The method for preventing tripping of the low-voltage feeder switch of the coal mine due to short-time voltage fluctuation, applied to the system for preventing tripping of the low-voltage feeder switch of the coal mine due to short-time voltage fluctuation according to any one of claims 1-2, characterized in that, The method comprises the following steps: The transformer (2) and the rectifier bridge (3) are used for detecting the voltage of the main circuit or the control circuit in real time, and the obtained voltage signal is input to the energy storage control module; the control circuit in the energy storage control module judges whether the current voltage state meets the preset condition of the charging state or the power supply state according to the voltage measurement result; When the voltage is greater than the charging voltage control constant value, the energy storage circuit enters the charging state and stores electric energy; when the voltage is lower than the power supply voltage control constant value, the power supply state is switched to and the timing is started; In the power supply state, a stable voltage is provided for the loss voltage release coil (4) to maintain its attraction state, so that the circuit breaker (1) is kept closed to supply power; if the voltage is restored to the charging voltage control constant value within the power supply time constant value, the charging state is switched to again; if the voltage is not restored within the set power supply time, the power supply output is controlled to be cut off; After the power supply is cut off, the loss voltage release coil (4) loses power, drives the circuit breaker (1) to trip, cuts off the main circuit, and realizes the time-delay tripping function; When the inverter energy storage power supply (11) is used, the inverter circuit (15) converts the energy storage electric energy into alternating voltage in the power supply state, provides dynamic voltage compensation for the main load, and suppresses the power grid fluctuation and harmonic interference; After the power supply is cut off, the discharge circuit two (17) is started to release the residual electric energy in the energy storage circuit two (14), so as to guarantee the system and personnel safety.

Images