Load simulation device and method for power distribution real-type test

Abstract

The load simulation device and method for power distribution real-type test belong to the technical field of real-type test of power distribution network. The whole device includes a load device for real-type test of power distribution network, a collection system and a test control platform. The present invention is connected to the whole switch circuit with load by a 10Kv power supply through a line, the switch circuit control platform controls the opening and closing state of the switch, the measuring unit measures the electrical quantity, and the waveform automatic analysis system automatically reads the value and analyzes it; the test device is developed based on the principle that different types of fuses have different melting times under the same current to control the fuse opening, and the fuse inlet and outlet are connected to the grounding switch through the grounding switch. The device is easy to install and transport, the control switch system is safe and reliable, the acquisition system has high wave recording accuracy, and the test is safe and reliable during operation.

Description

Technical Field

[0001] The invention relates to a load simulation device and method for power distribution true type test, belonging to the technical field of power distribution network true type test. Background Art

[0002] With the continuous development of distribution network technology, the research on single-phase grounding fault technology has become more and more in-depth, and new fault handling technologies such as neutral point fault current full compensation technology and grounding point fault current transfer technology have emerged. It is necessary to verify the effect of the rapid handling technology of single-phase line break fault in the distribution network. The existing technology does not have the test conditions for real line break tests with load, and it is impossible to verify the fault judgment, arc extinguishing, compensation and other functional effects of the installed and put into operation single-phase line break grounding fault new equipment and new technology under the condition of line break test with load. Summary of the invention

[0003] The present invention provides a load simulation device and method for a power distribution real-type test, which solves the technical problem in the prior art that fault analysis, arc extinguishing and compensation cannot be performed.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] The power distribution real test load simulation device includes an electrical primary structure, a test platform and an acquisition system. In the electrical primary structure, the low-voltage side of the transformer is connected in series with an adjustable electronic device and a circuit breaker K2; the high-voltage side of the transformer is connected in series in sequence from the power supply direction to the transformer direction with a circuit breaker K1, an isolating switch and a fuse; both ends of the fuse of the phase to be tested on the high-voltage side of the transformer are grounded through grounding switches T1 and T2 respectively.

[0006] The test platform includes an AC / DC power supply, a touch screen, a host computer, RS485 communication, a PLC, and a switch controller. The AC / DC power supply is connected to the touch screen, the PLC, and the switch controller; the host computer is connected to the touch screen; the touch screen is connected to the PLC via RS485 communication, and the signal output end of the PLC is connected to the switch controller; the switch controller controls the on and off of the circuit breaker K1, the circuit breaker K2, the isolating switch, the grounding switch T1, and the grounding switch T2.

[0007] The acquisition system includes a measuring unit, the output end of the measuring unit is connected to an oscilloscope, and the signal output end of the oscilloscope is connected to a display screen; the measuring unit includes a damped voltage divider, which is connected to both sides of the phase fuse to be detected and is used to detect voltage; the measuring unit includes a Rogowski coil, the signal output end of the Rogowski coil is connected to the oscilloscope through an integrating amplifier, and the Rogowski coil is connected between the grounding switch T1 and the ground medium and between the grounding switch T2 and the ground medium and is used to detect current.

[0008] The method for conducting a simulation experiment using the power distribution real-type test load simulation device comprises the following steps:

[0009] 1) Determine the resistance value of the adjustable resistor by the required current value;

[0010] 2) Calculate the current on the high-voltage side of the transformer through the adjustable electronic resistance, and then determine the specifications of the fuses installed in the A, B, and C phase fuses through the current value on the high-voltage side of the transformer;

[0011] 3) Select the grounding medium for the experiment, connect the Rogowski coil between the grounding switch T1 and the grounding medium, between the grounding switch T2 and the grounding medium, and connect the damped voltage divider to both sides of the phase fuse to be tested;

[0012] 4) Fuse closing;

[0013] 5) Through the switch controller of the test platform, control the isolating switch, circuit breaker K2, and circuit breaker K1 to close in sequence;

[0014] 6) When the fuse in the test phase blows, the switch controller controls the grounding switch T1 and the grounding switch T2 to close;

[0015] 7) According to the current and voltage values ​​on the power supply side recorded by the oscilloscope, the automatic data analysis system can calculate the current inrush value, the steady-state current effective value, the transient zero-sequence current amplitude, the transient zero-sequence voltage value, and the transient negative-sequence voltage value. By analyzing the data, it can be verified whether the line selection switch action in the front-end power grid is correct.

[0016] Beneficial effects created by the present invention: The present invention proposes a power distribution real-type test load simulation device and method, which has the test requirements of single-phase broken line grounding fault with load, as well as a diversified acquisition system and a safe and reliable switch control platform, and has the test conditions that meet different media as grounding points. The switch control platform is safe and reliable, the test loop device is simple to operate and quick to arrange, the oscilloscope has high recording accuracy, and there are many acquisition channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the electrical primary schematic diagram of the power distribution real-type test load simulation device in Example 1.

[0018] Figure 2 Schematic diagram of the switch control platform in Example 1.

[0019] Figure 3 This is the secondary principle diagram of the control loop in Example 1.

[0020] Figure 4 This is a schematic diagram of the acquisition system in Example 1.

[0021] Figure 5This is a schematic diagram of the acquisition position of the damped voltage divider and the Rogowski coil of the measurement unit of the present invention. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments.

[0023] The power distribution real test load simulation device includes an electrical primary structure, a test platform and an acquisition system. In the electrical primary structure, the low-voltage side of the transformer is connected in series with an adjustable electronic device and a circuit breaker K2; the high-voltage side of the transformer is connected in series in sequence from the power supply direction to the transformer direction with a circuit breaker K1, an isolating switch and a fuse; both ends of the fuse of the phase to be tested on the high-voltage side of the transformer are grounded through grounding switches T1 and T2 respectively.

[0024] The test platform includes an AC / DC power supply, a touch screen, a host computer, RS485 communication, a PLC, and a switch controller. The AC / DC power supply is connected to the touch screen, the PLC, and the switch controller; the host computer is connected to the touch screen; the touch screen is connected to the PLC via RS485 communication, and the signal output end of the PLC is connected to the switch controller; the switch controller controls the on and off of the circuit breaker K1, the circuit breaker K2, the isolating switch, the grounding switch T1, and the grounding switch T2.

[0025] The acquisition system includes a measuring unit, the output end of the measuring unit is connected to an oscilloscope, and the signal output end of the oscilloscope is connected to a display screen; the measuring unit includes a damped voltage divider, which is connected to both sides of the phase fuse to be detected and is used to detect voltage; the measuring unit includes a Rogowski coil, the signal output end of the Rogowski coil is connected to the oscilloscope through an integrating amplifier, and the Rogowski coil is connected between the grounding switch T1 and the ground medium and between the grounding switch T2 and the ground medium and is used to detect current.

[0026] The method for conducting a simulation experiment using the power distribution real-type test load simulation device comprises the following steps:

[0027] 1) Determine the resistance value of the adjustable resistor by the required current value;

[0028] 2) Calculate the current on the high-voltage side of the transformer through the adjustable electronic resistance, and then determine the specifications of the fuses installed in the A, B, and C phase fuses through the current value on the high-voltage side of the transformer;

[0029] 3) Select the grounding medium for the experiment, connect the Rogowski coil between the grounding switch T1 and the grounding medium, between the grounding switch T2 and the grounding medium, and connect the damped voltage divider to both sides of the phase fuse to be tested;

[0030] 4) Fuse closing;

[0031] 5) Through the switch controller of the test platform, control the isolating switch, circuit breaker K2, and circuit breaker K1 to close in sequence;

[0032] 6) When the fuse in the test phase blows, the switch controller controls the grounding switch T1 and the grounding switch T2 to close;

[0033] 7) According to the current and voltage values ​​on the power supply side recorded by the oscilloscope, the automatic data analysis system can calculate the current inrush value, the steady-state current effective value, the transient zero-sequence current amplitude, the transient zero-sequence voltage value, and the transient negative-sequence voltage value. By analyzing the data, it can be verified whether the line selection switch action in the front-end power grid is correct.

[0034] Embodiment 1:

[0035] This embodiment takes the simulation of the C phase disconnection fault power supply side grounding as an example, and describes the specific implementation steps in conjunction with the accompanying drawings:

[0036] Determine the test conditions: Select the test grounding medium and connect and fix it with the grounding wire. Use insulators to isolate the connection wire from the non-grounding medium.

[0037] Load test device: By adjusting the resistance, the current on the high voltage side of the transformer is calculated. Figure 1 As shown, taking the high voltage side of the transformer 30A as an example, 100A fuses are installed on the A and B phase fuses, and 6.3A fuses are installed on the C phase fuse. After the fuse is blown, the T1 grounding switch is closed and connected to the grounding medium to simulate the grounding of the power supply side of the C phase disconnection fault. After installation and fixation, the fuse is manually closed. The operator quickly evacuates to a safe area.

[0038] The control loop platform of the present invention includes two parts: a hardware system and a host computer software system, wherein the hardware system includes: power supply AC / DC, PLC controller, switch controller, touch screen, RS485 communication. Figure 2 As shown. The power supply AC / DC is connected to the touch screen and PLC controller through lines. The touch screen is connected to the PLC controller through RS485 communication, and the upper computer software system is embedded in the touch screen. The control line of the PLC controller is connected to the switch controller.

[0039] The device status indicator lights on the touch screen panel include: running, i.e., red light; stopping, i.e., green light; and fault, i.e., yellow light. The opening and closing states of each switch are uploaded to the touch screen by the PLC controller through communication. RS485 communication technology is used between the touch screen and the PLC controller in the present invention for data exchange. The parameters or instructions on the touch screen are transmitted to the PLC controller via RS485 communication, and the PLC controller controls the switch controller and then controls the opening and closing of the switch. The red light is on when the device is closed, and the green light is on when it is opened. The use of a touch screen can not only reduce the overall volume of the control loop, but also make it more convenient and flexible to set the opening and closing time. The order of opening and closing of each switch and the control of the opening and closing action time can be set on the touch screen panel, and the device can also realize the opening and closing action function through the module in the upper computer software. When the switch state is faulty, the test is automatically stopped, and the panel displays the end of the test or fault information.

[0040] according to Figure 2 As shown, the switch control circuit consists of AC / DC power supply, touch screen, PLC controller and switch controller. The touch screen is connected to the PLC controller through RS485 communication technology, and the PLC controller is connected to the switch controller through the control line to send action instructions. In the touch screen interface, closing means red light; opening means green light; and fault means yellow light. The disconnector is a visible break. During the test, the disconnector is closed by controlling the touch screen, and the K2 circuit breaker is automatically closed after 5s. After the switch operates normally, the PLC controller automatically closes the K1 circuit breaker after 5s. If the switch operates abnormally, that is, it cannot be switched as required, the PLC controller will automatically interrupt the test and disconnect the switch in sequence, and display the fault information on the touch screen. The incoming line end of the K1 circuit breaker is a 10Kv power supply. After closing, the entire test circuit is energized. When the C phase fuse is disconnected, the PLC controller controls the T2 grounding switch to close. This single-phase line break fault grounding test is completed.

[0041] like Figure 3 The figure shows the secondary principle diagram of the control circuit of the present invention. The touch screen is powered by a DC 24V power supply, and the switch controller is powered by AC220. The input end is connected to the opening and closing terminals of each switch controller. The input end is connected to the opening and closing indication terminals of each switch controller.

[0042] according to Figure 4 The acquisition system shown is composed of a measuring unit, an oscilloscope, and an automatic data analysis system. The measuring unit is composed of a damped voltage divider, a Rogowski coil, and an integral amplifier with high measuring accuracy and convenient measurement position change.

[0043] Measurement location Figure 5As shown, the damping voltage divider is connected to the inlet and outlet ends of the fuse to collect the fault voltage values ​​at both ends of the fault phase fuse and the non-fault phase fuse, and the Rogowski coil is installed between the T1 and T2 grounding switches and the grounding medium to collect the fault current values ​​at both ends of the broken line. The outlet end of the Rogowski coil is connected to the integral amplifier, and the outlet end of the integral amplifier and the outlet end of the damping voltage divider are connected to the oscilloscope. The oscilloscope has the characteristics of high-precision recording function and multi-channel acquisition function. The automatic data analysis system can intuitively display the read current inrush value, steady-state current effective value and transient zero-sequence current amplitude and other related fault current and voltage values ​​on the display screen, and can also be observed and analyzed in the form of graphics or data tables with previously collected data. The acquisition system triggers the acquisition at the same time when the K1 and K2 circuit breakers are closed. After the acquisition is completed, the waveform and the analysis results of the collected data are observed on the display screen. According to the current and voltage values ​​on the power supply side recorded by the oscilloscope, the automatic data analysis system can calculate the current inrush value, the steady-state current effective value, the transient zero-sequence current amplitude, the transient zero-sequence voltage value, the transient negative-sequence voltage value, etc. The data analysis can verify whether the line selection switch action is correct. Disconnect the test power supply, and after the discharge is completed, connect the grounding rod to the three disconnector breaks, replace the grounding medium, and conduct the next test condition test.

[0044] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure, including the claims, is limited to these examples; within the spirit of the present invention, the technical features in the above embodiments or in different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0045] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The power distribution real test load simulation device includes an electrical primary structure, a test platform and a collection system, and is characterized by: In the electrical primary structure, the low-voltage side of the transformer is connected in series with an adjustable electronic device and a circuit breaker K2; the high-voltage side of the transformer is connected in series with a circuit breaker K1, an isolating switch, and a fuse in sequence from the power supply direction to the transformer direction; both ends of the fuse of the phase to be detected on the high-voltage side of the transformer are grounded through grounding switches T1 and T2 respectively; The test platform includes a power supply AC / DC, a touch screen, a host computer, RS485 communication, a PLC, and a switch controller. The power supply AC / DC is connected to the touch screen, the PLC, and the switch controller; the host computer is connected to the touch screen; the touch screen is connected to the PLC via RS485 communication, and the signal output end of the PLC is connected to the switch controller; the switch controller controls the on and off of the circuit breaker K1, the circuit breaker K2, the isolating switch, the grounding switch T1, and the grounding switch T2; The acquisition system includes a measuring unit, the output end of the measuring unit is connected to an oscilloscope, and the signal output end of the oscilloscope is connected to a display screen; the measuring unit includes a damped voltage divider, which is connected to both sides of the phase fuse to be detected and is used to detect voltage; the measuring unit includes a Rogowski coil, the signal output end of the Rogowski coil is connected to the oscilloscope through an integrating amplifier, and the Rogowski coil is connected between the grounding switch T1 and the ground medium, and between the grounding switch T2 and the ground medium, and is used to detect current; The method for conducting a simulation experiment using the power distribution real-type test load simulation device comprises the following steps: 1) Determine the resistance value of the adjustable resistor by the required current value; 2) Calculate the current on the high-voltage side of the transformer through the adjustable electronic resistance, and then determine the specifications of the fuses installed in the A, B, and C phase fuses through the current value on the high-voltage side of the transformer; 3) Select the grounding medium for the experiment, connect the Rogowski coil between the grounding switch T1 and the grounding medium, between the grounding switch T2 and the grounding medium, and connect the damped voltage divider to both sides of the phase fuse to be tested; 4) Fuse closing; 5) Through the switch controller of the test platform, control the disconnector, circuit breaker K2, and circuit breaker K1 to close in sequence; 6) When the fuse in the test phase blows, the switch controller controls the grounding switch T1 and the grounding switch T2 to close; 7) According to the current and voltage values ​​on the power supply side recorded by the oscilloscope, the automatic data analysis system can calculate the current inrush value, the steady-state current effective value, the transient zero-sequence current amplitude, the transient zero-sequence voltage value, and the transient negative-sequence voltage value. By analyzing the data, it can be verified whether the line selection switch action in the front-end power grid is correct.

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