An electrical fault simulation device and method
By employing a DC safe voltage power supply and PLC control in the electrical fault simulation device, three-phase imbalance and poor contact faults are simulated, solving the problems of limited functionality and insufficient safety in existing technologies. This achieves safe and controllable electrical fault simulation and provides an intuitive and quantitative fault experience.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUBEI POLYTECHNIC INST
- Filing Date
- 2026-03-11
- Publication Date
- 2026-06-09
AI Technical Summary
Existing electrical fault simulation devices are limited in function, incomplete in measurement, outdated in control, and lack sufficient safety. Furthermore, setting up faults in real equipment carries high risks and cannot be repeated.
It adopts DC safe voltage power supply, simulates electrical faults by simulating loads through three-phase unbalanced heating and poor contact heating, uses PLC to control the on and off of relays, measures voltage, current, resistance and temperature in real time, establishes a relationship model, and provides controllable and repeatable fault simulation by combining safety modules and measurement systems.
It achieves safe, controllable, and repeatable electrical fault simulation, providing an intuitive and quantitative fault experience and avoiding high-risk operations on real equipment.
Smart Images
Figure CN122176996A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrical fault simulation technology, and in particular to an electrical fault simulation device and method. Background Technology
[0002] Electrical fault simulation is an important training and research tool for ensuring the safe operation of power systems. Currently, it mainly employs methods such as theoretical teaching, setting up faults on real equipment, or software simulation. However, theoretical teaching is not intuitive; setting faults on real equipment carries extremely high risks, is destructive, and cannot be repeated; software simulation lacks a sense of physical reality. Existing simple simulation devices generally suffer from drawbacks such as limited functionality, incomplete measurement capabilities, outdated control systems, and insufficient safety. Summary of the Invention
[0003] The purpose of this invention is to address the problems of limited functionality, incomplete measurement, outdated control, and insufficient safety in existing electrical fault simulation methods. This invention proposes an electrical fault simulation device and method, wherein the method includes the following steps: Connect each phase and neutral line of the 380V three-phase power supply to the AC terminal of the switching power supply. Each switching power supply is connected to a three-phase unbalanced heating simulated load; Each three-phase unbalanced heating simulation load is connected in parallel with a poor contact heating simulation load; Relays are used to control the switching power supply between the three-phase unbalanced heating simulated load and the poor contact heating simulated load; Use a PLC to control the on / off state of the relay; It also measures the load's voltage, current, resistance, and temperature in real time. Establish a model of the relationship between voltage, current, resistance and temperature to determine the degree of danger and safety threshold under different fault conditions.
[0004] Furthermore, the three-phase unbalanced heating simulation load uses heating wires, and the resistance values of the three three-phase unbalanced heating simulation loads can be adjusted.
[0005] Furthermore, the three simulated loads for poor contact heating are either PTC heating elements or wire-wound resistors; the wire-wound resistors are used to simulate static poor contact, and the PTC heating elements are used to simulate dynamic poor contact.
[0006] Furthermore, the relationship between the resistance and temperature of the PTC heating element can be divided into the following three stages: Phase 1: After the power is turned on, the PTC begins to heat up on its own; Phase Two: The PTC temperature rises to its Curie point, and the relationship between temperature and resistance is expressed by the following formula:
[0007] in, This indicates the resistance of the PTC at temperature T. Indicates reference temperature The resistance is given by A, where A is a material constant. Phase 3: The temperature stabilizes at the equilibrium temperature of the PTC.
[0008] Furthermore, in a three-phase unbalanced fault, the current imbalance is the ratio of the difference between the maximum and minimum phase currents to the average phase current.
[0009] The present invention also proposes an electrical fault simulation device for implementing the above-mentioned method, comprising: 380V three-phase power supply module, multiple switching power supplies, multiple relays, multiple three-phase unbalanced heating simulation loads, poor contact heating simulation loads, PLC, safety module and measurement system; The measurement system is used to measure the voltage, current, and temperature of the load.
[0010] Furthermore, the three-phase power module includes: a circuit breaker and a residual current device (RCD).
[0011] Furthermore, the safety module includes an axial fan, a temperature switch, and a cooling fan. The axial fan and cooling fan are used to dissipate heat from the simulated load, and the temperature switch is used to disconnect the three-phase power module when the detected temperature of the simulated load exceeds a set threshold.
[0012] The beneficial effects of the technical solution provided by this invention are: This invention uses a safe DC voltage as its core power supply. It simulates the heating of wires caused by three-phase imbalance through heating wires, and simulates the heating of heat sources caused by faults such as poor contact and loose contacts through PTC ceramic heating elements. It also uses PLC to achieve intelligent control. This invention provides a safe, controllable and repeatable electrical fault simulation device and method that is isolated from the real power grid, operates under a safe voltage, and can reproduce the phenomenon of high-voltage faults. It provides an intuitive and quantitative fault experience. Attached Figure Description
[0013] Figure 1 This is a flowchart of an electrical fault simulation method according to an example of the present invention. Detailed Implementation
[0014] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0015] Three-phase imbalance in a power system is mainly caused by imbalance in three-phase loads. Three-phase imbalance will lead to additional heating and vibration of rotating motors, increased leakage flux and local overheating of transformers, increased power grid line losses, and malfunction of various protection and automatic devices, etc.
[0016] Poor contact refers to a lack of proper contact between two or more electrical connection points in a circuit, preventing the normal flow of current. This situation usually causes equipment to malfunction and may even damage the circuit. The causes of poor contact are varied, including physical damage, oxidation, and dirt. Poor contact can lead to safety hazards such as short circuits or fires, especially in high-voltage equipment.
[0017] A flowchart of an electrical fault simulation method according to an example of the present invention is shown below. Figure 1 Specifically, it includes: To simulate a three-phase imbalance fault, this invention connects a load to each single-phase line of a 380V AC three-phase power supply. To avoid direct operation on high-voltage (380V AC) lines, this invention converts the AC power to 24V DC power and connects a 24V switching power supply to each single-phase line. Specifically, each phase and neutral line are connected to the AC terminal of the switching power supply. The voltage between each phase and neutral line of the 380V three-phase power supply is 220V AC. Phase A and neutral line N are connected to the live and neutral terminals of the first switching power supply; phase B and neutral line N are connected to the live and neutral terminals of the second switching power supply; and phase C and neutral line N are connected to the live and neutral terminals of the third switching power supply. In this invention, all three switching power supplies are the same 24V switching power supply.
[0018] Connect a three-phase unbalanced heating simulation load to the 24V DC terminal of each switching power supply. The three-phase unbalanced heating simulation load consists of three sets of power resistors (such as high-power wire-wound resistors) or heating wires with different resistances. The purpose of setting the three three-phase unbalanced heating simulation loads with different resistances is to create an unbalanced three-phase current. With different resistances, the current in each line is also different, according to Joule's law (Q=I). 2 The phase line with the higher current (RT) generates significantly more heat under load, thus visually demonstrating the localized overheating phenomenon caused by imbalance. The resistance value of the three-phase unbalanced heating simulation load can be adjusted, thereby adjusting the current value to simulate the severity of the fault. Alternatively, multiple sets of three-phase unbalanced heating simulation loads with varying resistance values from low to high can be connected in parallel, and the switching on and off of different sets can be controlled by a PLC.
[0019] Each three-phase unbalanced heating simulation load is connected in parallel with a poor contact heating simulation load. The purpose of this invention is to ensure that the poor contact heating simulation load and the three-phase unbalanced heating simulation load are connected in parallel so that they do not interfere with each other when simulating independent poor contact and three-phase unbalanced faults. The three poor contact heating simulation loads are identical PTC heating elements or wire-wound resistors; the wire-wound resistors are used to simulate static poor contact, and the PTC heating elements are used to simulate dynamic poor contact.
[0020] Poor contact can be divided into two situations: Static poor contact: such as a corroded joint, whose resistance is basically fixed, can be simulated using a high-resistance wire-wound resistor.
[0021] Dynamic contact defects, such as electrostatic oxidation, are exacerbated by rising temperatures, causing a sharp increase in resistance. PTC (Polymerized Tolerant Coating) exhibits the following characteristics: rising temperature → sharp increase in material resistivity → rising equivalent resistance → reaching equilibrium temperature. Both PTC and dynamic contact defects involve a process where resistance increases sharply with increasing temperature.
[0022] The relationship between the resistance and temperature of a PTC heating element can be divided into the following three stages: Phase 1: After the power is turned on, the PTC begins to heat up on its own; Phase Two: As the PTC temperature rises to near its Curie point, the relationship between temperature and resistance is expressed by the following formula:
[0023] in, This indicates the resistance of the PTC at temperature T. Indicates reference temperature The resistance is given by A, where A is a material constant. Phase 3: The temperature stabilizes at the equilibrium temperature of the PTC.
[0024] This invention uses a ceramic PTC heating element, model PTC-24V / 50W, with a working voltage of 24V, a rated power of 8W, and a maximum surface temperature of 150℃. It has constant temperature characteristics to avoid overheating and runaway.
[0025] Two experiments were conducted on the PTC: heat dissipation and heat insulation. The PTC's temperature and loop current were recorded, and real-time curves were plotted to demonstrate the impact of heat dissipation failures. Adding a heat sink to the PTC resulted in a decrease in equilibrium temperature, a decrease in resistance, and an increase in current. Then, wrapping it with insulation cotton resulted in an increase in equilibrium temperature, an increase in resistance, and a decrease in current. This visually demonstrates the significant impact of the heat dissipation environment on the severity of the fault.
[0026] Relays were used to control the switching on and off of a three-phase unbalanced overheating simulated load and a poor-contact overheating simulated load with the switching power supply. The normally open contacts of the relays were connected in series in the faulty load circuit, acting as a switch for the load power supply. The relay coils were controlled by the PLC output. During the experiment, the voltage, current, resistance, and temperature of the load were measured in real time. A model of the relationship between voltage, current, resistance, and temperature was established to determine the degree of danger and safety thresholds under different fault conditions.
[0027] In this invention, the experimental procedure is as follows: (1) Power on: Turn on the main switch and the three-phase power supply module is powered on. The 24V switching power supply starts and supplies power to the PLC and relay coils. The PLC starts and enters standby mode.
[0028] (2) Select fault mode: The operator selects the type of fault to be simulated (such as three-phase imbalance or poor contact) through the human-machine interface.
[0029] (3) Parameter settings: Set simulation parameters (such as configuration of unbalanced load, simulation duration, etc.).
[0030] (4) Start simulation: The operator presses the closing control signal of the corresponding relay coil. After receiving the signal, the PLC drives the corresponding relay coil to close.
[0031] (5) Due to unbalanced load or poor contact, the analog resistor begins to glow red and heat up.
[0032] (6) Monitoring and Stopping: The operator can observe the temperature changes of the load and the "fault point". After the set time is reached, the PLC automatically shuts off the output, the relay disconnects, and the load is de-energized. In case of emergency, pressing the emergency stop button will directly cut off all control circuits and the load will be de-energized immediately.
[0033] (7) Reset: After troubleshooting (e.g., after cooling), the device is reset via the safety module and returns to standby mode.
[0034] The three-phase imbalance simulation steps are as follows: The three-phase imbalance simulation is initiated for 10 minutes and then automatically shut down. Real-time measurements of the voltage, current, resistance, and temperature of each simulated load phase are taken. In a three-phase imbalance fault, the current imbalance is calculated as the ratio of the difference between the maximum and minimum phase currents to the average phase current. The power imbalance is calculated as the ratio of the difference between the maximum and minimum phase power to the average phase power.
[0035] The steps for simulating poor contact are as follows: The PLC output signal synchronously controls the relays of the PTC heating elements in the three circuits to close, connecting the power supply and simulating overheating due to poor contact; when the selection is canceled, the relays open, stopping the heating. The voltage, current, resistance, and temperature of each phase of the simulated load are measured in real time. Synchronous control of the PTC heating elements in the three circuits avoids the impact of three-phase imbalance caused by controlling only one circuit, which would affect the measurement results.
[0036] The present invention also proposes an electrical fault simulation device for implementing the above-mentioned method, comprising: 380V three-phase power supply module, multiple switching power supplies, multiple relays, multiple three-phase unbalanced heating simulation loads, poor contact heating simulation loads, PLC, safety module and measurement system; The measurement system is used to measure the voltage, current, and temperature of the load.
[0037] Three-phase power modules include circuit breakers and residual current devices (RCDs).
[0038] The safety module includes an axial fan, a temperature switch, and a cooling fan. The axial fan and cooling fan are used to dissipate heat from the simulated load, and the temperature switch disconnects the three-phase power module when the detected simulated load temperature exceeds a set threshold. After a single test, the axial fan and cooling fan are activated to accelerate the cooling of the heating wire.
[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An electrical fault simulation method, characterized in that, include: Connect each phase and neutral line of the 380V three-phase power supply to the AC terminal of the switching power supply. Each switching power supply is connected to a three-phase unbalanced heating simulated load; Each three-phase unbalanced heating simulation load is connected in parallel with a poor contact heating simulation load; Relays are used to control the switching power supply between the three-phase unbalanced heating simulated load and the poor contact heating simulated load; Use a PLC to control the on / off state of the relay; Real-time measurement of load voltage, current, resistance, and temperature; Establish a model of the relationship between voltage, current, resistance and temperature to determine the degree of danger and safety threshold under different fault conditions.
2. The electrical fault simulation method according to claim 1, characterized in that, The three-phase unbalanced heating simulation load uses heating wires, and the resistance values of the three three-phase unbalanced heating simulation loads can be adjusted.
3. The electrical fault simulation method according to claim 1, characterized in that, The three simulated loads for poor contact and heat generation are either PTC heating elements or wire-wound resistors; the wire-wound resistors are used to simulate static poor contact, and the PTC heating elements are used to simulate dynamic poor contact.
4. The electrical fault simulation method according to claim 3, characterized in that, The relationship between the resistance and temperature of a PTC heating element can be divided into the following three stages: Phase 1: After the power is turned on, the PTC begins to heat up on its own; Phase Two: The PTC temperature rises to its Curie point, and the relationship between temperature and resistance is expressed by the following formula: in, This indicates the resistance of the PTC at temperature T. Indicates reference temperature The resistance is given by A, where A is a material constant. Phase 3: The temperature stabilizes at the equilibrium temperature of the PTC.
5. The electrical fault simulation method according to claim 1, characterized in that, In a three-phase unbalanced fault, the current unbalance is the ratio of the difference between the maximum and minimum phase currents to the average phase current.
6. An electrical fault simulation device, characterized in that, The method for implementing any one of claims 1-5 includes: 380V three-phase power supply module, multiple switching power supplies, multiple relays, multiple three-phase unbalanced heating simulation loads, poor contact heating simulation loads, PLC, safety module and measurement system; The measurement system is used to measure the voltage, current, and temperature of the load.
7. An electrical fault simulation device according to claim 6, characterized in that, The three-phase power supply module includes: a circuit breaker and a residual current device (RCD).
8. An electrical fault simulation device according to claim 6, characterized in that, The safety module includes an axial fan, a temperature switch, and a cooling fan. The axial fan and cooling fan are used to dissipate heat from the simulated load, and the temperature switch is used to disconnect the three-phase power module when the detected temperature of the simulated load exceeds a set threshold.