CN106093674A - Use short circuit current self-powered electric network fault detection device and method - Google Patents

Abstract

The invention discloses a power grid fault detection device adopting short-circuit current self-supply power supply, comprising a current transformer, a rectification circuit, a microprocessor, a reverse discharge protection diode D1, a forward discharge diode D2, a DC voltage conversion circuit, a bidirectional switch and Supercapacitor; the positive output terminal of the rectifier circuit is connected with a bypass switch, and the negative output terminal of the rectifier circuit is connected with a current detection circuit; the anode of the forward discharge diode D2 is connected to the cathode of the reverse discharge protection diode D1, and the positive terminal of the supercapacitor is connected to the cathode of the reverse discharge protection diode D1. Two-way switch connection, the cathode of the forward discharge diode D2 is also connected with a voltage detection circuit; the microprocessor is connected with a wireless communication module, and the output terminal of the microprocessor is connected with a bypass switch control and drive circuit and a two-way switch control and drive circuit . The invention also discloses a power grid fault detection method using short-circuit current self-powered. The circuit structure of the invention is simple, the detection method steps are simple, the degree of intelligence is high, and the working reliability is high.

Description

Power grid fault detection device and method using short-circuit current self-powered

technical field

The invention belongs to the technical field of power grid fault detection, and in particular relates to a power grid fault detection device and method using short-circuit current self-powered.

Background technique

The safe, stable, and reliable operation of the power system has important economic significance for production and user electricity consumption, so it is necessary to monitor and control the power grid in real time to improve the safety and reliability of its operation. When faults such as short circuit or open circuit occur in the power grid line, the fault can be detected in time, and the fault information will be sent to the control center to notify the maintenance personnel, to eliminate the fault in time and restore power operation. The fault detection device is a kind of electric power facility, which has a large number of applications in the supporting facilities of the power grid. It detects line faults through sensor devices, cooperates with the signal processing module to realize fault type judgment, and uses the wireless transmission module to send fault information to the control center to realize fault detection. Detect and send. The existing on-line detection device for power lines is located in a remote location, and it is difficult to solve the power supply problem by conventional methods. Currently, the power supply used for fault detection of transmission lines usually uses solar panels, voltage transformers to obtain power from the grid, and current transformers to obtain power from the power grid. Power is obtained by means of online power acquisition, wind and solar hybrid, ground wire induction, etc., and the solution of battery energy storage is used to realize the power supply of the detection device. However, the work of solar panels is affected by weather, climate, geography, etc., and there are certain defects in actual use; the wind and solar hybrid scheme is suitable for places with long sunshine hours and sufficient wind; grounding wire induction power needs to be installed in the new laying or power grid transformation design with lightning protection It is used on transmission lines of overhead lines; voltage transformers and current transformers are directly installed on transmission lines, and are widely used.

There are currently several methods for power grid fault detection devices: method (1) use solar panels and batteries to supply power, use transformers to realize fault detection, use ZigBee to realize short-distance information transmission, and send fault signals to the box under the tower Station, the wireless equipment in the box sends signals to the control center to realize fault information reporting; method (2) uses current or voltage transformers to directly take power, cooperate with lithium batteries to supply power, and detect faults at the same time as the transformers take energy. ZigBee realizes short-distance information transmission, transmits the fault information to the nearest transmission sub-station, and then sends it to the upper-level terminal from the sub-station to realize the reporting of fault information; method (3) use current transformer or voltage transformer with lithium battery or storage battery Realize the energy supply of the device, detect the fault while the transformer takes energy, and use the GSM wireless module to directly send the fault information to the control center remotely. For method (1), the whole device is divided into two parts, the volume is large, and the solar panel is affected by weather, geography, and climate, and the power supply performance is unstable; for method (2), there is also the problem of method (1). It consists of two parts, which are large in size and complicated to install; for the method (3), the current transformer or voltage transformer cooperates with the storage battery or lithium battery to realize power supply. influences.

To sum up, the power grid fault detection devices in the prior art all have certain deficiencies in use, and cannot well meet actual use requirements.

Contents of the invention

The technical problem to be solved by the present invention is to provide a simple circuit structure, reasonable design, high degree of intelligence, high working reliability, strong practicability, good use effect, and easy to popularize and use. A short-circuit current self-powered grid fault detection device.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a power grid fault detection device using short-circuit current self-powered, characterized in that it includes a current transformer for taking power from the power grid line when the power grid line is short-circuited And the rectification circuit connected with the output terminal of current transformer, and microprocessor, reverse discharge protection diode D1, forward discharge diode D2, DC voltage conversion circuit, bidirectional switch and supercapacitor; The positive pole output terminal of described rectification circuit A bypass switch is connected, and the negative output terminal of the rectification circuit is connected with a current detection circuit for real-time detection of the current on the secondary side of the current transformer, and the current detection circuit is connected with the bypass switch; the reverse discharge The anode of the protection diode D1 is connected to the positive output end of the rectifier circuit and the bypass switch, the anode of the forward discharge diode D2 and the bidirectional switch are connected to the cathode of the reverse discharge protection diode D1, and the anode of the supercapacitor is connected to the bidirectional switch. Switch connection, the negative pole of the supercapacitor is grounded, the input terminal of the DC voltage conversion circuit is connected to the cathode of the forward discharge diode D2, and the cathode of the forward discharge diode D2 is also connected to the input for the DC voltage conversion circuit A voltage detection circuit for real-time detection of voltage; the microprocessor is connected with a wireless communication module, the output end of the current detection circuit and the output end of the voltage detection circuit are connected with the input end of the microprocessor, and the microprocessor The output terminal of the device is connected with a bypass switch control and drive circuit and a bidirectional switch control and drive circuit, the bypass switch is connected with the output terminal of the bypass switch control and drive circuit, and the bidirectional switch and the bidirectional switch control and drive circuit output connection.

The above-mentioned power grid fault detection device adopting short-circuit current self-power supply is characterized in that: the rectification circuit is a full-bridge rectification circuit composed of diode D3, diode D4, diode D5 and diode D6, and the cathode of the diode D3 is connected to the diode D4 The anode of the diode is connected to the first AC signal input terminal AC1 of the rectifier circuit, the cathode of the diode D6 is connected to the anode of the diode D5 and is the second AC signal input terminal AC2 of the rectifier circuit, the cathode of the diode D4 is connected to the diode D5 The cathode of the diode D3 is connected to the positive DC voltage output terminal V+ of the rectifier circuit, the anode of the diode D3 is connected to the anode of the diode D6 and is the negative DC voltage output terminal V- of the rectifier circuit; the first AC signal input of the rectifier circuit The terminal AC1 is connected to one terminal of the secondary side of the current transformer, and the second AC signal input terminal AC2 of the rectifier circuit is connected to the other terminal of the secondary side of the current transformer.

The above-mentioned power grid fault detection device using short-circuit current self-powered is characterized in that: the DC voltage conversion circuit includes a voltage conversion chip U1, a polar capacitor C1 and a polar capacitor C2, and the input terminal pin of the voltage conversion chip U1 VIN is the input terminal of the DC voltage conversion circuit and is connected to the positive pole of the polar capacitor C1, the output pin OUT of the voltage conversion chip U1 is the output terminal VCC of the DC voltage conversion circuit and is connected to the positive pole of the polar capacitor C2, The ground pin GND of the voltage conversion chip U1, the negative poles of the polar capacitor C1 and the negative pole of the polar capacitor C2 are all grounded.

The above-mentioned power grid fault detection device using short-circuit current self-power supply is characterized in that: the bidirectional switch is an enhanced PMOS transistor Q2, and the gate of the enhanced PMOS transistor Q2 is connected to the output end of the bidirectional switch control and drive circuit, The anode of the supercapacitor is connected to the drain of the enhanced PMOS transistor Q2, and the source of the enhanced PMOS transistor Q2 is connected to the cathode of the reverse discharge protection diode D1.

The above-mentioned power grid fault detection device adopting short-circuit current self-power supply is characterized in that: the bidirectional switch control and drive circuit includes a triode VT2, a resistor R3, a resistor R4 and a resistor R5, and one end of the resistor R5 is a bidirectional switch control and drive circuit. The control signal input end of the circuit is connected to the output end of the microprocessor, the base of the triode VT2 is connected to the other end of the resistor R5, the emitter of the triode VT2 is grounded, and the collector of the triode VT2 is connected to the resistor R4 One end of the resistor R4 is connected to the output end of the bidirectional switch control and drive circuit, and the other end of the resistor R4 is connected to the cathode of the reverse discharge protection diode D1 through the resistor R3.

The above-mentioned power grid fault detection device using short-circuit current self-power supply is characterized in that: the bypass switch is an enhanced NMOS transistor Q1, and the gate of the enhanced NMOS transistor Q1 is connected to the output terminal of the bypass switch control and drive circuit connected, the drain of the enhanced NMOS transistor Q1 is connected to the positive output terminal of the rectifier circuit; the current detection circuit is composed of a current sampling resistor Rs, one end of the current sampling resistor Rs is connected to the enhanced NMOS transistor Q1 The source is connected, and the other end of the current sampling resistor Rs is the output end of the current detection circuit, and is connected with the negative output end of the rectification circuit.

The above-mentioned power grid fault detection device using short-circuit current self-power supply is characterized in that: the bypass switch control and drive circuit includes a triode VT1, a resistor R1 and a resistor R2, and one end of the resistor R1 is a bypass switch control and drive circuit The control signal input end of the transistor VT1 is connected to the output end of the microprocessor, the base of the triode VT1 is connected to the other end of the resistor R1, the collector of the triode VT1 is connected to one end of the resistor R2, and the other end of the resistor R2 One end is connected to the cathode of the forward discharge diode D2, and the emitter of the triode VT1 is the output end of the bypass switch control and drive circuit.

The above-mentioned power grid fault detection device powered by short-circuit current is characterized in that: the microprocessor is a mixed signal processor, and the wireless communication module is a GSM wireless communication module.

The above-mentioned power grid fault detection device adopting short-circuit current self-power supply is characterized in that: the voltage detection circuit is composed of a resistor R6 and a resistor R7 connected in series, and one end of the resistor R6 and the resistor R7 connected in series is connected to the cathode of the forward discharge diode D2 connected, the other end of the resistor R6 and the resistor R7 connected in series are grounded, and the connecting end of the resistor R6 and the resistor R7 is the output end of the voltage detection circuit. The present invention also provides a method for detecting a fault in a power grid using short-circuit current self-supply with simple method steps and convenient implementation. It is characterized in that the specific process of the method is as follows:

Connect the primary side of the current transformer to the grid line;

When a short-circuit fault occurs in the grid line and an instantaneous large current is generated in the grid line, a large current flows through the primary side of the current transformer, and the current coupled to the secondary side of the current transformer first supplies power to the DC voltage conversion circuit through the rectifier circuit The DC voltage conversion circuit generates the working voltage required by the microprocessor and the wireless communication module, and the microprocessor and the wireless communication module start to work normally; the current detection circuit detects the current on the secondary side of the current transformer in real time and converts the detected The current signal is converted into the input voltage of the microprocessor and output to the microprocessor. When the input voltage of the microprocessor output by the current detection circuit reaches the interrupt trigger voltage of the microprocessor, the microprocessor interrupts the processing and transmits the fault signal through wireless communication. The module sends it to the control center; the voltage detection circuit detects the input voltage of the DC voltage conversion circuit in real time and outputs the detected signal to the microprocessor, and the microprocessor compares the input voltage detection value of the DC voltage conversion circuit it receives with the Compared with the charging start voltage preset in the microprocessor, when the input voltage detection value of the DC voltage conversion circuit is greater than the charging start voltage preset in the microprocessor, the microprocessor outputs a control signal to the bidirectional The switch control and drive circuit, the bidirectional switch control and drive circuit drive the bidirectional switch to conduct, and the DC current output by the rectifier circuit passes through the reverse discharge protection diode D1 to charge and store energy for the supercapacitor; when the input voltage detection value of the DC voltage conversion circuit is greater than When the charging stop voltage is preset in the microprocessor, the microprocessor outputs a control signal to the bypass switch control and drive circuit, the bypass switch control and drive circuit drives the bypass switch to conduct, and the DC current output by the rectifier circuit passes through The bypass switch forms a circulation loop;

When a short-circuit fault occurs in the grid line and the fault protection circuit breaker in the grid line trips, the supercapacitor acts as a backup power supply and supplies power to the DC voltage conversion circuit through a bidirectional switch, thereby continuing to provide stable working voltage for the microprocessor and wireless communication module , to ensure the normal operation of the microprocessor and the wireless communication module, and the microprocessor continues to send fault signals to the control center through the wireless communication module.

Compared with the prior art, the present invention has the following advantages:

1. The circuit structure of the power grid fault detection device self-powered by short-circuit current of the present invention is simple, reasonable in design, and convenient to implement.

2. When the power grid fault detection device using short-circuit current self-power supply of the present invention is used, when the power grid line is running normally, the power grid line current is small, and the device is in a dormant working mode as a whole. When a short-circuit fault occurs in the line, the device starts to work, and the power low consumption.

3. The present invention uses current transformers to take power from the grid lines, and supplemented by supercapacitor energy storage to realize uninterrupted power supply for the grid fault detection device. Compared with the traditional method, this method takes into account the power grid fault detection device. The size and service life are unmatched by traditional methods. Because current transformers are cheaper than voltage transformers, and can be easily installed inside the distribution switch box or made into openings and directly hung on the distribution line, so for For the fault detection of overhead lines, the power supply method using current transformers to obtain electricity and store energy in supercapacitors is a very promising power supply method.

4. The present invention uses a current transformer to take power from the grid line, which can realize the isolation of high voltage and low voltage, and ensure that after the primary side fails, the grid fault detection device can still work safely and reliably, and is especially suitable for grids that require high A system for voltage fault signal detection.

5. The present invention adopts supercapacitors with high power density, long service life, environmental protection, and wide operating temperature range as the backup energy storage device. The reliability of the backup power supply is high, which ensures the reliability of the entire power grid fault detection device.

6. The present invention makes full use of the huge short-circuit energy generated when the power grid line is short-circuited, uses a current transformer to take power, stores energy in a supercapacitor, and realizes self-supply, which provides a new idea for the power supply scheme of the power grid line fault detection device.

7. The opening of the bidirectional switch and the bypass switch of the present invention utilizes the internal analog comparator of the microprocessor to cooperate with the driving circuit of the external triode tube to realize, the fault judgment utilizes the interruption of the microprocessor to realize, and the judgment and detection are realized by a microprocessor , reducing the complexity of the circuit structure.

8. The present invention can send fault signals to the control center in real time by setting up a wireless communication module, realizing remote automatic monitoring and intelligentization of power grid faults.

9. The grid fault detection method adopting short-circuit current self-supply of the present invention has simple steps and is easy to implement.

10. The present invention can be conveniently used for power grid fault detection, and can timely notify the power grid line control center and arrange maintenance personnel to eliminate faults in time and restore power operation, which can reduce economic losses caused by power faults to a certain extent.

To sum up, the circuit structure of the present invention is simple, the design is reasonable, the detection method steps are simple, the degree of intelligence is high, the work reliability is high, the practicability is strong, the use effect is good, and it is easy to popularize and use.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a schematic circuit block diagram of a power grid fault detection device using short-circuit current self-supply in the present invention.

Fig. 2 is a schematic circuit diagram of a power grid fault detection device using short-circuit current self-supply according to the present invention.

Explanation of reference signs:

1—rectifier circuit; 2—current detection circuit; 3—bypass switch;

4—DC voltage conversion circuit; 5—bidirectional switch; 6—super capacitor;

7—wireless communication module; 8—microprocessor; 9—bypass switch control and drive circuit;

10—two-way switch control and drive circuit; 11—voltage detection circuit; 12—current transformer.

detailed description

As shown in Fig. 1 and Fig. 2, the power grid fault detection device adopting short-circuit current self-supply of the present invention includes the current transformer 12 and the connection between the current transformer 12 and the current transformer 12 for taking power from the grid line when a short circuit occurs in the grid line. The rectification circuit 1 connected to the output terminal, and the microprocessor 8, the reverse discharge protection diode D1, the forward discharge diode D2, the DC voltage conversion circuit 4, the bidirectional switch 5 and the supercapacitor 6; the positive output terminal of the rectification circuit 1 A bypass switch 3 is connected, and the negative output terminal of the rectifier circuit 1 is connected with a current detection circuit 2 for real-time detection of the current on the secondary side of the current transformer 12, and the current detection circuit 2 is connected with the bypass switch 3 The anode of the reverse discharge protection diode D1 is connected to the positive output terminal of the rectifier circuit 1 and the bypass switch 3, and the anode of the forward discharge diode D2 and the bidirectional switch 5 are connected to the cathode of the reverse discharge protection diode D1 , the positive pole of the supercapacitor 6 is connected to the bidirectional switch 5, the negative pole of the supercapacitor 6 is grounded, the input terminal of the DC voltage conversion circuit 4 is connected to the cathode of the forward discharge diode D2, and the forward discharge diode D2 The cathode is also connected with a voltage detection circuit 11 for real-time detection of the input voltage of the DC voltage conversion circuit 4; the microprocessor 8 is connected with a wireless communication module 7, and the output terminal of the current detection circuit 2 and the voltage detection The output terminals of the circuit 11 are all connected to the input terminals of the microprocessor 8, and the output terminals of the microprocessor 8 are connected with a bypass switch control and drive circuit 9 and a bidirectional switch control and drive circuit 10, and the bypass switch 3 It is connected with the output terminal of the bypass switch control and drive circuit 9 , and the bidirectional switch 5 is connected with the output terminal of the bidirectional switch control and drive circuit 10 .

As shown in Figure 2, in this embodiment, the rectifier circuit 1 is a full-bridge rectifier circuit composed of diode D3, diode D4, diode D5 and diode D6, the cathode of the diode D3 is connected to the anode of the diode D4 and is The first AC signal input terminal AC1 of the rectifier circuit 1, the cathode of the diode D6 is connected to the anode of the diode D5 and is the second AC signal input terminal AC2 of the rectifier circuit 1, and the cathode of the diode D4 is connected to the cathode of the diode D5 And it is the positive DC voltage output terminal V+ of the rectification circuit 1, the anode of the diode D3 is connected to the anode of the diode D6 and is the negative DC voltage output terminal V- of the rectification circuit 1; the first AC signal input of the rectification circuit 1 The terminal AC1 is connected to one terminal of the secondary side of the current transformer 12 , and the second AC signal input terminal AC2 of the rectifier circuit 1 is connected to the other terminal of the secondary side of the current transformer 12 .

As shown in Figure 2, in this embodiment, the DC voltage conversion circuit 4 includes a voltage conversion chip U1, a polar capacitor C1 and a polar capacitor C2, the input pin VIN of the voltage conversion chip U1 is a DC voltage conversion The input terminal of the circuit 4 is connected to the positive pole of the polarity capacitor C1, the output pin OUT of the voltage conversion chip U1 is the output terminal VCC of the DC voltage conversion circuit 4 and is connected to the positive pole of the polarity capacitor C2, the voltage The ground pin GND of the conversion chip U1, the negative poles of the polar capacitor C1 and the negative poles of the polar capacitor C2 are all grounded. During specific implementation, the voltage conversion chip U1 is a chip LM7805;

As shown in Figure 2, in this embodiment, the bidirectional switch 5 is an enhanced PMOS transistor Q2, the gate of the enhanced PMOS transistor Q2 is connected to the output terminal of the bidirectional switch control and drive circuit 10, and the supercapacitor The anode of 6 is connected to the drain of the enhanced PMOS transistor Q2, and the source of the enhanced PMOS transistor Q2 is connected to the cathode of the reverse discharge protection diode D1.

As shown in Figure 2, in this embodiment, the bidirectional switch control and drive circuit 10 includes a triode VT2, a resistor R3, a resistor R4 and a resistor R5, and one end of the resistor R5 is the control signal of the bidirectional switch control and drive circuit 10 The input terminal is connected to the output terminal of the microprocessor 8, the base of the triode VT2 is connected to the other end of the resistor R5, the emitter of the triode VT2 is grounded, and the collector of the triode VT2 is connected to one end of the resistor R4 , the other end of the resistor R4 is the output end of the bidirectional switch control and driving circuit 10, and is connected to the cathode of the reverse discharge protection diode D1 through the resistor R3.

As shown in Figure 2, in this embodiment, the bypass switch 3 is an enhanced NMOS transistor Q1, the gate of the enhanced NMOS transistor Q1 is connected to the output end of the bypass switch control and drive circuit 9, and the The drain of the enhanced NMOS transistor Q1 is connected to the positive output terminal of the rectifier circuit 1; the current detection circuit 2 is composed of a current sampling resistor Rs, and one end of the current sampling resistor Rs is connected to the source of the enhanced NMOS transistor Q1 The other end of the current sampling resistor Rs is the output end of the current detection circuit 2 and is connected to the negative output end of the rectification circuit 1 .

As shown in Figure 2, in this embodiment, the bypass switch control and drive circuit 9 includes a triode VT1, a resistor R1 and a resistor R2, and one end of the resistor R1 is the control signal input of the bypass switch control and drive circuit 9 terminal and connected to the output terminal of the microprocessor 8, the base of the triode VT1 is connected to the other end of the resistor R1, the collector of the triode VT1 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the resistor R2. The cathode of the forward discharge diode D2 is connected, and the emitter of the triode VT1 is the output end of the bypass switch control and drive circuit 9 .

As shown in Fig. 2, in this embodiment, the microprocessor 8 is a mixed signal processor, and the wireless communication module 7 is a GSM wireless communication module. During specific implementation, the microprocessor 8 is an MSP430 series low-power mixed-signal processor, and the model of the GSM wireless communication module is SIM900.

As shown in Figure 2, in this embodiment, the voltage detection circuit 11 is composed of a resistor R6 and a resistor R7 connected in series, one end of the resistor R6 and R7 connected in series is connected to the cathode of the forward discharge diode D2, and the The other end of the resistor R6 and the resistor R7 are grounded, and the connecting end of the resistor R6 and the resistor R7 is the output end of the voltage detection circuit 11 .

The grid fault detection method using short-circuit current self-powered power supply of the present invention, the specific process is:

Connect the primary side of the current transformer 12 to the grid line;

When a short-circuit fault occurs in the grid line and an instantaneous (tens of milliseconds) large current is generated in the grid line, a large current flows through the primary side of the current transformer 12, and the current coupled to the secondary side of the current transformer 12 passes through the rectifier circuit 1 first supply power to the DC voltage conversion circuit 4, the DC voltage conversion circuit 4 generates the working voltage required by the microprocessor 8 and the wireless communication module 7, and the microprocessor 8 and the wireless communication module 7 start to work normally; the current detection circuit 2 controls the current The current on the secondary side of the transformer 12 is detected in real time and the detected current signal is converted into the input voltage of the microprocessor 8 and output to the microprocessor 8. When the input voltage of the microprocessor 8 output by the current detection circuit 2 reaches the microprocessor 8 When the interrupt trigger voltage of the processor 8, the microprocessor 8 processes the interrupt and sends the fault signal to the control center through the wireless communication module 7; the voltage detection circuit 11 detects the input voltage of the DC voltage conversion circuit 4 in real time and detects the The signal is output to the microprocessor 8, and the microprocessor 8 compares the input voltage detection value of the DC voltage conversion circuit 4 it receives with the charging start voltage preset in the microprocessor 8, when the DC voltage conversion circuit When the input voltage detection value of 4 is greater than the charging start voltage preset in the microprocessor 8, the microprocessor 8 outputs a control signal to the bidirectional switch control and drive circuit 10, and the bidirectional switch control and drive circuit 10 drives the bidirectional switch 5 Conduction, the DC current output by the rectifier circuit 1 passes through the reverse discharge protection diode D1 to charge and store energy for the supercapacitor 6; when the input voltage detection value of the DC voltage conversion circuit 4 is greater than the preset value in the microprocessor 8, the charging stops voltage, the microprocessor 8 outputs a control signal to the bypass switch control and drive circuit 9, the bypass switch control and drive circuit 9 drives the bypass switch 3 to conduct, and the DC current output by the rectifier circuit 1 passes through the bypass switch 2 to form a flow circuit; at this time, the supercapacitor 6 is in the float charge mode;

When a short-circuit fault occurs in the grid line and the fault protection circuit breaker in the grid line trips, the supercapacitor 6 serves as a backup power supply, and supplies power to the DC voltage conversion circuit 4 through the bidirectional switch 5, thereby continuing to provide power for the microprocessor 8 and the wireless communication module 7 Provide a stable working voltage to ensure the normal operation of the microprocessor 8 and the wireless communication module 7, and the microprocessor 8 continues to send fault signals to the control center through the wireless communication module 7.

The present invention uses a current transformer to take power from the grid line, and supplemented with supercapacitor energy storage to realize uninterrupted power supply for the grid fault detection device. Compared with the traditional method, this method takes into account the size and size of the grid fault detection device The service life is unmatched by traditional methods, which ensures the reliability of the entire power grid fault detection device.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technical aspects of the present invention. within the scope of protection of the scheme.

Claims (10)

1. one kind uses short circuit current self-powered electric network fault detection device, it is characterised in that: include at power network line When short circuit occurs from power network line the current transformer (12) of power taking and whole with what the outfan of current transformer (12) was connected Current circuit (1), and microprocessor (8), back discharge protection diode D1, forward discharge diode D2, DC voltage conversion Circuit (4), two-way switch (5) and super capacitor (6)；The cathode output end of described rectification circuit (1) is connected to by-pass switch (3), The cathode output end of described rectification circuit (1) is connected to for detecting the electric current of current transformer (12) secondary side in real time Current detection circuit (2), described current detection circuit (2) is connected with by-pass switch (3)；Described back discharge protection diode D1 Anode be connected with cathode output end and the by-pass switch (3) of rectification circuit (1), the anode of described forward discharge diode D2 and Two-way switch (5) all protects the negative electrode of diode D1 to be connected with back discharge, the positive pole of described super capacitor (6) and two-way switch (5) connect, the minus earth of described super capacitor (6), the input of described DC voltage converting circuit (4) and forward electric discharge two The negative electrode of pole pipe D2 connects, and the negative electrode of described forward discharge diode D2 is further connected with for DC voltage converting circuit (4) The voltage detecting circuit (11) that input voltage detects in real time；Wireless communication module (7) it is connected on described microprocessor (8), The outfan of described current detection circuit (2) and the outfan of voltage detecting circuit (11) all with the input of microprocessor (8) Connecting, the outfan of described microprocessor (8) is connected to by-pass switch controlling and driving circuits (9) and two-way switch controls and drives Circuit (10), described by-pass switch (3) is connected with the outfan of by-pass switch controlling and driving circuits (9), described two-way switch (5) outfan with two-way switch controlling and driving circuits (10) is connected.

2. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described Rectification circuit (1) is the full bridge rectifier being made up of diode D3, diode D4, diode D5 and diode D6, described two The negative electrode of pole pipe D3 is connected with the anode of diode D4 and for the first AC signal input AC1 of rectification circuit (1), and described two The negative electrode of pole pipe D6 is connected with the anode of diode D5 and for the second AC signal input AC2 of rectification circuit (1), and described two The negative electrode of pole pipe D4 is connected with the negative electrode of diode D5 and for the positive DC voltage output end V+ of rectification circuit (1), and described two The anode of pole pipe D3 is connected and is the negative DC voltage output end V-of rectification circuit (1) with the anode of diode D6；Described whole First AC signal input AC1 of current circuit (1) is connected with one end of the secondary side of current transformer (12), described rectified current The second AC signal input AC2 on road (1) is connected with the other end of the secondary side of current transformer (12).

3. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described DC voltage converting circuit (4) includes voltage conversion chip U1, polar capacitor C1 and polar capacitor C2, described voltage conversion chip The input that input pin VIN is DC voltage converting circuit (4) of U1 and being connected with the positive pole of polar capacitor C1, described electricity The outfan VCC that outfan pin OUT is DC voltage converting circuit (4) and with polar capacitor C2 just of pressure conversion chip U1 Pole connects, and the negative pole of earth terminal pin GND, the negative pole of polar capacitor C1 and the polar capacitor C2 of described voltage conversion chip U1 is equal Ground connection.

4. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described Two-way switch (5) is enhancement mode PMOS Q2, the grid of described enhancement mode PMOS Q2 and two-way switch controlling and driving circuits (10) outfan connects, and the positive pole of described super capacitor (6) is connected with the drain electrode of described enhancement mode PMOS Q2, described enhancing The source electrode of type PMOS Q2 is connected with the negative electrode of back discharge protection diode D1.

5. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described Two-way switch controlling and driving circuits (10) includes audion VT2, resistance R3, resistance R4 and resistance R5, the one of described resistance R5 End is the control signal input of two-way switch controlling and driving circuits (10) and is connected with the outfan of microprocessor (8), institute The other end of the base stage and resistance R5 of stating audion VT2 is connected, the grounded emitter of described audion VT2, described audion VT2 Colelctor electrode be connected with one end of resistance R4, the other end of described resistance R4 is the defeated of two-way switch controlling and driving circuits (10) Go out end, and be connected by the negative electrode of resistance R3 with back discharge protection diode D1.

6. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described By-pass switch (3) is enhancement mode NMOS tube Q1, the grid of described enhancement mode NMOS tube Q1 and by-pass switch controlling and driving circuits (9) outfan connects, and the drain electrode of described enhancement mode NMOS tube Q1 is connected with the cathode output end of rectification circuit (1)；Described electricity Current detection circuit (2) is made up of current sampling resistor Rs, one end of described current sampling resistor Rs and described enhancement mode NMOS tube The source electrode of Q1 connects, the outfan that the other end is current detection circuit (2) of described current sampling resistor Rs, and and rectification circuit (1) cathode output end connects.

7. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described By-pass switch controlling and driving circuits (9) includes audion VT1, resistance R1 and resistance R2, and one end of described resistance R1 is bypass On-off control and the control signal input of drive circuit (9) and be connected with the outfan of microprocessor (8), described audion The base stage of VT1 is connected with the other end of resistance R1, and the colelctor electrode of described audion VT1 is connected with one end of resistance R2, described electricity The other end of resistance R2 is connected with the negative electrode of described forward discharge diode D2, the transmitting extremely by-pass switch of described audion VT1 The outfan of controlling and driving circuits (9).

8. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described Microprocessor (8) is mixed-signal processor, and described wireless communication module (7) is gsm wireless communication module.

9. detect device according to the self-powered electric network fault of employing short circuit current described in claim 1, it is characterised in that: described Voltage detecting circuit (11) is made up of the resistance R6 connected and resistance R7, resistance R6 after series connection and one end of resistance R7 and forward The negative electrode of discharge diode D2 connects, the resistance R6 after series connection and the other end ground connection of resistance R7, described resistance R6 and resistance R7 The outfan that connection end is voltage detecting circuit (11).

10. utilize the method that electric network fault as claimed in claim 1 detection device carries out electric network fault detection, its feature Being, the detailed process of the method is:

The primary side of current transformer (12) is received on power network line；

When power network line is short-circuited fault and makes to produce transient high-current in power network line, current transformer (12) is once Side has big electric current to flow through, and the electric current of the secondary side being coupled to current transformer (12) passes through rectification circuit (1) first to unidirectional current Voltage conversion circuit (4) is powered, and DC voltage converting circuit (4) produces required for microprocessor (8) and wireless communication module (7) Running voltage, microprocessor (8) and wireless communication module (7) start normal work；Current detection circuit (2) is to current transformer (12) electric current of secondary side detects in real time and that the current signal detected is converted to the input voltage of microprocessor (8) is defeated Going out to microprocessor (8), the input voltage of the microprocessor (8) exported when current detection circuit (2) reaches microprocessor (8) During down trigger voltage, microprocessor (8) processes and interrupts, and is sent by wireless communication module (7) by fault-signal in extremely controlling The heart；The letter that the input voltage of DC voltage converting circuit (4) is detected and will detect by voltage detecting circuit (11) in real time Number output to microprocessor (8), the input voltage measurement of the DC voltage converting circuit (4) that microprocessor (8) is received Value is compared with the charging starting voltage being set in advance in microprocessor (8), when the input electricity of DC voltage converting circuit (4) Pressure detected value is more than when being set in advance in the charging starting voltage in microprocessor (8), and microprocessor (8) output control signal is given Two-way switch controlling and driving circuits (10), two-way switch controlling and driving circuits (10) drives two-way switch (5) conducting, rectification The DC current that circuit (1) exports gives super capacitor (6) charging energy-storing after back discharge protection diode D1；Work as unidirectional current When the input voltage measurement value of voltage conversion circuit (4) stops voltage more than the charging being set in advance in microprocessor (8), micro-place Reason device (8) output control signal drives to by-pass switch controlling and driving circuits (9), by-pass switch controlling and driving circuits (9) By-pass switch (3) turns on, and the DC current that rectification circuit (1) exports forms flow cycle through by-pass switch (2)；

When power network line is short-circuited fault and makes the error protection circuit breaker trip in power network line, super capacitor (6) is made For back-up source, power to DC voltage converting circuit (4) by two-way switch (5), thus continue as microprocessor (8) and nothing Line communication module (7) provides stable running voltage, it is ensured that microprocessor (8) and the normal work of wireless communication module (7), micro- Processor (8) continues through wireless communication module (7) and sends fault-signal to control centre.