Partial discharge detecting and positioning device for power system

Abstract

The invention discloses a partial discharge detecting and positioning device for a power system. The partial discharge detecting and positioning device comprises an ultrasonic sensor array, a signal conditioning circuit, a controller and a display and positioning device, the ultrasonic sensor array is composed of a plurality of ultrasonic sensors and used for monitoring the discharge phenomenon in the power equipment and transmitting collected electric signals to the signal conditioning circuit. The signal conditioning circuit is used for converting signals collected by the ultrasonic sensor into pulse signals and transmitting the pulse signals to the controller, the controller processes the pulse signals, time difference calculation and positioning are carried out, and the position of partial discharge is displayed through the display screen and indicated through the steering engine. The partial discharge phenomenon and the position of the partial discharge phenomenon can be conveniently and quickly found by inspection personnel and faults can be eliminated, accurate detection and positioning indication of the partial discharge phenomenon in the power equipment are realized, the inspection efficiency of the power equipment is greatly improved, and the safe operation of a power system is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of partial discharge detection devices in power systems, and particularly relates to a partial discharge detection and positioning device for power systems. BACKGROUND

[0002] As the core equipment of power systems, the operation stability of switch cabinets is directly related to the overall safety of power grids. Due to the long-term work of switch cabinets in high ambient temperature and high voltage environment, the internal insulation materials will gradually age and even deteriorate, the insulation performance of the materials will gradually deteriorate, and even partial discharge phenomenon will occur. The aggravation of partial discharge will further cause the deterioration of insulation performance, and eventually cause power system failure, power outage accident and even fire.

[0003] In addition to switch cabinets, partial discharge phenomenon also occurs in devices such as transformers and generators. The reason is that the insulation materials gradually age under high temperature and high pressure. Regular monitoring of partial discharge phenomenon in power systems is of great significance to ensure the safe and reliable operation of high-voltage equipment.

[0004] At present, the partial discharge detection products on the market mainly include the following types: detecting the voltage signal generated by partial discharge through a transient ground voltage sensor; detecting the electromagnetic wave signal generated by partial discharge through an antenna; detecting the vibration sound wave signal generated by partial discharge through an ultrasonic sensor; and detecting the light signal generated by partial discharge through an optical sensor.

[0005] These products can monitor the occurrence of partial discharge phenomenon in real time and provide alarm information. Further based on the monitoring data, through algorithm analysis, the fault can be predicted. However, the current products are difficult to locate and indicate the specific position of partial discharge. When the product detects the partial discharge phenomenon, manual intervention inspection is needed to further determine the specific position of partial discharge. SUMMARY

[0006] The present application provides a partial discharge detection and positioning device for power systems, which can detect partial discharge of the product and obtain the position of partial discharge through signal conversion and calculation, improve the efficiency of power equipment inspection, and ensure the safe operation of the system.

[0007] To achieve the above purpose, the technical scheme provided by the present application is:

[0008] A partial discharge detection and positioning device for power systems, comprising: an ultrasonic sensor array, a signal conditioning circuit, a controller, and a display and positioning device.

[0009] The ultrasonic sensor array comprises a plurality of ultrasonic sensors for collecting ultrasonic signals generated by partial discharge.

[0010] The ultrasonic sensor array is connected with a signal conditioning circuit, and the signal conditioning circuit is used for preprocessing the ultrasonic signal;

[0011] The signal conditioning circuit is connected with a controller, and the controller is used for performing partial discharge positioning calculation by using the preprocessed ultrasonic signal: calculating the time difference between each pulse signal corresponding to each ultrasonic sensor in the ultrasonic sensor array, converting the coordinate solving problem of the partial discharge into extreme value calculation by using an analog annealing algorithm, and calculating and determining the occurrence position of the partial discharge phenomenon;

[0012] The display and positioning device is connected with the controller, and the display and positioning device displays and / or indicates the partial discharge position according to the partial discharge positioning result obtained by the controller.

[0013] In order to optimize the above technical scheme, the specific measures taken also include:

[0014] The ultrasonic sensor array includes four ultrasonic sensors P1, P2, P3 and P4, the coordinates of the four ultrasonic sensors are respectively P1(x1, y1, z1), P2(x2, y2, z2), P3(x3, y3, z3) and P4(x4, y4, z4), and the position coordinates of the partial discharge source S are S(x, y, z); the time when the ultrasonic signal emitted by the partial discharge source S reaches the four ultrasonic sensors is respectively t1, t2, t3 and t4, and the equation group is as follows:

[0015]

[0016] Further, the above equation group is converted into the following equation group by using the method of constructing an optimization problem for indirect solving:

[0017]

[0018] In the formula:

[0019] Δt1 represents the time difference between t2 and t1, Δt2 represents the time difference between t3 and t1, Δt3 represents the time difference between t4 and t1, L1 represents the value obtained by subtracting the distance difference calculated by the time difference method from the actual distance difference between the P2 sensor, the P1 sensor and the partial discharge source S, L2 represents the value obtained by subtracting the distance difference calculated by the time difference method from the actual distance difference between the P3 sensor, the P1 sensor and the partial discharge source S, and L3 represents the value obtained by subtracting the distance difference calculated by the time difference method from the actual distance difference between the P4 sensor, the P1 sensor and the partial discharge source S;

[0020] Further, the expression of the target function L is obtained:

[0021]

[0022] Further, when and only when L=0, the solution x, y, z of the equation group is obtained, and the partial discharge position S(x, y, z) is obtained. Further, when applied to actual power equipment, the area where the partial discharge may occur has a certain range, and an optimization problem can be constructed accordingly.

[0023] Further, the ultrasonic sensor array is uniformly and equidistantly distributed on the printed circuit board, and an interface of a signal acquisition circuit is reserved on the circuit board to obtain the best signal receiving effect and positioning accuracy when monitoring the partial discharge phenomenon.

[0024] The ultrasonic sensor can monitor weak discharge activities in real time, and can work in a wide frequency range, and can be suitable for various insulating materials. The ultrasonic sensor is a non-contact detection method, which is very suitable for high-voltage power systems and has good safety.

[0025] Further, the signal conditioning circuit comprises a high-pass filter circuit, a same-phase amplification circuit and a hysteresis comparison circuit connected in sequence, and the signal conditioning circuit converts the preprocessed analog signal into a pulse signal and then sends it to the controller.

[0026] Further, the high-pass filter circuit adopts a high-pass filter circuit based on an NE5532 operational amplifier, the same-phase amplification circuit adopts an OP37 operational amplifier chip, and the hysteresis comparison circuit adopts an integrated circuit TLV3501.

[0027] The NE5532DR is a high-performance dual operational amplifier, which has excellent frequency response and low distortion characteristics, ensuring the efficiency and stability of the filter circuit. The high-pass filter circuit based on the NE5532DR operational amplifier improves the anti-interference ability, filters out power frequency signals and other low-frequency electrical signals, and retains the ultrasonic signals generated during partial discharge.

[0028] The amplifier adopts an OP37 operational amplifier chip, which has a maximum offset voltage of 25uV and a maximum offset drift of 0.6uV / ℃. The chip is powered by dual power supply and has a gain bandwidth product of 63MHz, which is used for same-phase amplification of the output signal of the sensor.

[0029] The TLV3501 is a high-performance single-channel high-speed push-pull output hysteresis comparator, which has a fast response time of 4.5 nanoseconds, is suitable for a wide voltage power supply range of 2.7V to 5.5V, has rail-to-rail output capability, can directly drive CMOS or TTL logic circuits, and ensures voltage compatibility with the I / O port of the controller.

[0030] The controller adopts an STM32 single-chip microcomputer or a multi-core processor.

[0031] The pulse signal processed by the hysteresis comparison circuit is transmitted to the controller, the controller is responsible for calculating the time difference of arrival between the four pulse signals, and combining the simulated annealing algorithm to convert the coordinate solving problem into extreme value calculation. Through multiple iterations, the device can accurately determine the occurrence position of the partial discharge phenomenon, thereby realizing efficient fault positioning.

[0032] This method not only improves the accuracy of positioning, but also optimizes the efficiency of the calculation process, so that the device can still operate stably and reliably in complex environments.

[0033] Further, the display and positioning device comprises a serial screen and a rudder indicator, the serial screen is used to display the detection and positioning results according to the signals of the controller, and the rudder indicator is used to indicate the partial discharge position under the action of the controller.

[0034] The rudder indicator comprises a rudder and a laser pen arranged on the rudder, the rudder drives the laser pen to rotate so as to point to the partial discharge position.

[0035] The controller calculates the angle that the rudder needs to rotate according to the partial discharge positioning calculation result, the coordinate position of the rudder and the initial pointing direction of the laser pen, so that the laser pen on the rudder can point to the partial discharge position.

[0036] The working process of the controller comprises:

[0037] When performing partial discharge positioning calculation according to the signals of each ultrasonic sensor, the controller receives the pulse signal from the signal conditioning circuit, first judges whether it is the first pulse signal, if yes, performs parameter updating and records the pulse signal, then continues to receive and record the pulse signal, until the pulse signals corresponding to the number of ultrasonic sensors are received, and then uses the simulated annealing algorithm to calculate the partial discharge detection and positioning.

[0038] The beneficial effects of the present application are:

[0039] The device not only realizes accurate detection of partial discharge, but also can position the occurrence position and give light signal indication, so as to facilitate the inspection personnel to quickly find the partial discharge phenomenon and the position and eliminate the fault, realize accurate detection and positioning indication of the partial discharge phenomenon in the power equipment, greatly improve the efficiency of power equipment inspection, and ensure the safe operation of the power system. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The device circuit composition schematic diagram of the present application.

[0041] Figure 2 The ultrasonic sensor array layout diagram of the present application.

[0042] Figure 3 : High-pass filter circuit diagram of the present application.

[0043] Figure 4 : In-phase amplification circuit diagram of the present application.

[0044] Figure 5 : Hysteresis comparator circuit diagram of the present application.

[0045] Figure 6 : Flow chart of the controller for realizing the electric signal positioning.

[0046] Figure 7 : Partial discharge positioning model of the present application. DETAILED DESCRIPTION

[0047] The above content of the present application is further explained in detail in the form of a specific embodiment, but this should not be understood as the scope of the above subject matter of the present application being limited to the following examples only, and any technology realized based on the above content of the present application falls within the scope of the present application.

[0048] Unless otherwise specified, the terms used in the present application have the commonly understood meanings understood by those skilled in the art. Unless otherwise specified, the values of the parameters mentioned in the present application can be measured by various measurement methods commonly used in the art.

[0049] The present application provides a partial discharge detection and positioning device for power systems, as shown in Figures 1-5 The device comprises an ultrasonic sensor array, a signal conditioning circuit, a controller and a display and positioning device.

[0050] The ultrasonic sensor array comprises a plurality of ultrasonic sensors for collecting ultrasonic signals generated by partial discharge;

[0051] The ultrasonic sensor array is connected to the signal conditioning circuit, and the signal conditioning circuit is used for pre-processing the ultrasonic signals;

[0052] The signal conditioning circuit is connected to the controller, and the controller is used for partial discharge positioning calculation using the pre-processed ultrasonic signals;

[0053] The controller is connected to the display and positioning device, and the display and positioning device displays and indicates the position of the partial discharge according to the obtained partial discharge positioning result;

[0054] The partial discharge positioning calculation method is to calculate the time difference between each pulse signal corresponding to each ultrasonic sensor in the ultrasonic sensor array, and to convert the coordinate solving problem of the partial discharge into extreme value calculation by combining the simulated annealing algorithm, so as to calculate and determine the occurrence position of the partial discharge phenomenon.

[0055] In some embodiments, as Figure 2 When the device in the power system begins to appear partial discharge, the occurrence of the accompanying acousto-optic physical phenomenon, signal reception and positioning are carried out by using the four-element ultrasonic array;

[0056] P1, P2, P3, P4 in the figure are uniformly and equidistantly distributed on the printed circuit board, and the interface of the signal acquisition circuit is reserved on the circuit board to ensure that the best signal receiving effect and positioning accuracy can be obtained when monitoring the partial discharge phenomenon.

[0057] As Figure 3 The signal collected from the ultrasonic sensor is input as an input signal, the input signal enters the circuit through the J11 interface, is preliminarily amplified by the first-stage operational amplifier U4.1, the amplified signal is coupled to the second-stage operational amplifier U1.2 through the capacitor C17, the second-stage operational amplifier further processes the signal, and finally outputs the signal SIG1.1.

[0058] As Figure 4 After the power supply is turned on, C51 and C52 begin to charge to ensure that the power supply is stable, the SIG4.1 and SIG4.2 input signals enter the operational amplifier through the resistor and capacitor network, the operational amplifier amplifies according to the input signal and the feedback network, and the output signal is output from the OUT terminal, and the output signal is transmitted through SIG4.2 for use by the subsequent circuit.

[0059] As Figure 5 When the voltage of the input signal SIG4.2 changes, it will be compared with the fixed reference voltage, if the input signal voltage is higher than the reference voltage, the output signal will become low, and if the input signal voltage is lower than the reference voltage, the output signal will become high, thereby realizing the conversion of the electrical signal to the pulse signal.

[0060] In some embodiments, the electrical signal output by the sensor array is disturbed by the power frequency and other low-frequency signals, at this time, the high-pass filter circuit can effectively filter out the power frequency signal and other low-frequency electrical signals, and retain the ultrasonic signal generated during the partial discharge.

[0061] The signal output by the sensor is amplified through the in-phase amplification circuit, and the amplified signal is converted into a digital pulse signal by the hysteresis comparator and transmitted to the controller.

[0062] The controller is responsible for calculating the time difference of arrival between the four pulse signals, and combining the simulated annealing algorithm to convert the coordinate solving problem into an extreme value calculation. Through multiple iterations, the device can accurately determine the location of the partial discharge phenomenon, thereby realizing efficient fault positioning.

[0063] In some embodiments, as Figure 6As shown, the controller implements the flow of discharging signal positioning: the flow starts, initializes the pin, and prepares for subsequent operations; initializes the interrupt system to respond when a specific event occurs;

[0064] initializes the timer for subsequent calculation of the arrival time difference between the four pulse signals; waits for the first signal collected from the ultrasonic sensor to be converted into a pulse signal;

[0065] determines whether the currently received signal is the first pulse, if so, continue to the next step; if not, return to the pulse waiting state; after receiving the first pulse, update the parameters;

[0066] trigger the interrupt processing to respond to the pulse event; check whether the number of parameters has reached the corresponding number of pulse signals; if not, return to the parameter updating step to continue updating the parameters;

[0067] if so, continue to the next step; when the number of parameters corresponds to the number of pulse signals, apply the simulated annealing algorithm for processing; the processed parameters, i.e., the coordinate parameters, are displayed on the screen, and the flow ends.

[0068] In some embodiments, the display and positioning device includes a serial screen and a rudder indicator, the serial screen is used to display the detection and positioning results according to the signals of the controller, and the rudder indicator is used to indicate the partial discharge position under the action of the controller.

[0069] In some embodiments, the rudder indicator includes a rudder and a laser pen arranged on the rudder, the rudder drives the laser pen to rotate to point to the partial discharge position. The controller calculates the angle that the rudder needs to rotate according to the partial discharge positioning calculation result and the coordinate position of the rudder and the initial pointing direction of the laser pen, so that the laser pen on the rudder can point to the partial discharge position. As preferred, the controller converts the fault coordinates and the rudder coordinates into an angle and converts it into a duty cycle of a PWM wave, thereby controlling the rudder to rotate to the appropriate angle.

[0070] In some embodiments, as shown in Figure 7 The ultrasonic sensor array includes four ultrasonic sensors P1, P2, P3, and P4, and the coordinates of the four ultrasonic sensors are P1(x1, y1, z1), P2(x2, y2, z2), P3(x3, y3, z3), and P4(x4, y4, z4), respectively, and the position coordinates of the partial discharge source S are S(x, y, z); the times when the ultrasonic signals emitted by the partial discharge source S arrive at the four ultrasonic sensors are t1, t2, t3, and t4, respectively, and the equation set is listed as follows:

[0071]

[0072] The above equation group is converted into a construction optimization problem for indirect solution:

[0073]

[0074] In the formula:

[0075] Δt1 represents the time difference between t2 and t1, Δt2 represents the time difference between t3 and t1, Δt3 represents the time difference between t4 and t1, L1 represents the value of the actual distance difference between the P2 sensor, the P1 sensor and the partial discharge source S minus the distance difference calculated by the time difference method, L2 represents the value of the actual distance difference between the P3 sensor, the P1 sensor and the partial discharge source S minus the distance difference calculated by the time difference method, and L3 represents the value of the actual distance difference between the P4 sensor, the P1 sensor and the partial discharge source S minus the distance difference calculated by the time difference method;

[0076] The expression of the target function L is obtained:

[0077]

[0078] When L=0, the solutions x, y and z of the equation group are obtained, and the partial discharge position S(x, y, z) is obtained.

[0079] When applied to actual power equipment, there is a certain range of areas where partial discharge may occur, and an optimization problem can be constructed accordingly.

[0080] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any skilled person in the art can make any simple modification, equivalent replacement and improvement to the above embodiment according to the technical essence of the present application without departing from the scope of the technical solution of the present application, and all of the above still fall within the protection scope of the present application.

Claims

1. A partial discharge detection and positioning device for a power system, characterized in that: include: Ultrasonic sensor array, signal conditioning circuit, controller and display and positioning device; The ultrasonic sensor array comprises a number of ultrasonic sensors for collecting ultrasonic signals generated by partial discharge; The ultrasonic sensor array is connected to a signal conditioning circuit, and the signal conditioning circuit is used to pre-process the ultrasonic signal; The signal conditioning circuit is connected to a controller, which is used to perform partial discharge location calculation using the pre-processed ultrasonic signal: calculating the arrival time difference between the pulse signals corresponding to the ultrasonic sensors in the ultrasonic sensor array, and converting the partial discharge coordinate solution problem into an extreme value calculation in combination with a simulated annealing algorithm to calculate the location of the partial discharge phenomenon; The display and positioning device is connected to the controller, and the display and positioning device displays and / or indicates the partial discharge position according to the partial discharge positioning result obtained by the controller.

2. The power system partial discharge detection and positioning device according to claim 1, characterized in that: The ultrasonic sensor array includes four ultrasonic sensors P1, P2, P3, and P4. Assume that the coordinates of these four ultrasonic sensors are P1 (x1, y1, z1), P2 (x2, y2, z2), P3 (x3, y3, z3), and P4 (x4, y4, z4), respectively. The position coordinates of the partial discharge source S are S (x, y, z). Assume that the time it takes for the ultrasonic signal emitted by the partial discharge source S to reach the four ultrasonic sensors is t1, t2, t3, and t4, respectively. The equations are listed as follows: The above equations are transformed into the following by using the method of constructing the optimization problem for indirect solution: Wherein, Δt1 represents the time difference between t2 and t1, Δt2 represents the time difference between t3 and t1, Δt3 represents the time difference between t4 and t1, L1 represents the actual distance difference between the P2 sensor, the P1 sensor, and the local discharge source S minus the distance difference calculated using the time difference method, L2 represents the actual distance difference between the P3 sensor, the P1 sensor, and the local discharge source S minus the distance difference calculated using the time difference method, and L3 represents the actual distance difference between the P4 sensor, the P1 sensor, and the local discharge source S minus the distance difference calculated using the time difference method. The expression of the objective function L is obtained: If and only if L=0, the solutions x, y, z of the equation group are obtained, and the partial discharge position S(x, y, z) is obtained.

3. The power system partial discharge detection and positioning device according to claim 1, characterized in that: In the ultrasonic sensor array, each ultrasonic sensor is arranged on a printed circuit board, and a signal acquisition circuit interface is reserved on the printed circuit board.

4. The power system partial discharge detection and positioning device according to claim 1, characterized in that: The signal conditioning circuit comprises a high-pass filter circuit, a common-mode amplifier circuit and a hysteresis comparison circuit which are connected in sequence. The signal conditioning circuit converts the pre-processed analog signal into a pulse signal and then sends it to the controller.

5. The power system partial discharge detection and positioning device according to claim 4, characterized in that: The high-pass filter circuit adopts a high-pass filter circuit based on the NE5532 operational amplifier, the in-phase amplifier circuit adopts the OP37 operational amplifier chip, and the hysteresis comparison circuit adopts the integrated circuit TLV3501.

6. The power system partial discharge detection and positioning device according to claim 1, characterized in that: The controller adopts STM32 single chip microcomputer or multi-core processor.

7. The power system partial discharge detection and positioning device according to claim 1, characterized in that: The display and positioning device includes a serial port screen and a steering gear indicator. The serial port screen is used to display the detection and positioning results according to the signal of the controller, and the steering gear indicator is used to indicate the partial discharge position under the action of the controller.

8. The power system partial discharge detection and positioning device according to claim 7, characterized in that: The steering gear indicator comprises a steering gear and a laser pen arranged on the steering gear. The steering gear drives the laser pen to rotate so as to point to the partial discharge position.

9. The power system partial discharge detection and positioning device according to claim 8, characterized in that: The controller calculates the angle at which the servo needs to be rotated based on the partial discharge positioning calculation result, the coordinate position of the servo, and the initial direction of the laser pen, so that the laser pen on the servo can point to the partial discharge position.

10. The power system partial discharge detection and positioning device according to claim 1, characterized in that: When performing partial discharge location calculations based on the signals from each ultrasonic sensor, the controller receives a pulse signal from the signal conditioning circuit and first determines whether it is the first pulse signal. If so, it updates the parameters and records the pulse signal. It then continues to receive and record pulse signals until a number of pulse signals corresponding to the number of ultrasonic sensors are received. At this point, a simulated annealing algorithm is used to calculate partial discharge detection and location.

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