Boosting system and method for live-line training of live-line work

Abstract

The invention discloses a boosting system and method for live-line training of live-line work, and belongs to the technical field of live-line training, and the system comprises a 0.4 kV AC power supply, a full-control power electronic power switch, a power electronic power controller, a full-control power electronic low-voltage switch, a three-winding boosting transformer, a current sensor, a practical training line, a series reactor, and a control and protection unit. The left side of the full-control power electronic power switch is connected with a 0.4 kV alternating current power supply, and the right side is connected with a power electronic power controller; the right side of the power electronic power supply controller is connected with a three-winding boosting transformer through a full-control power electronic low-voltage switch; a neutral point of the three-winding step-up transformer is connected in series with a series reactor to be grounded; the right side of the current sensor is connected with a practical training line, and monitored current information is transmitted to the control and protection unit. And the control and protection unit controls the on-off of the full-control power electronic low-voltage switch. According to the invention, multiple voltage class requirements are met, and live-line training is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of live-line training, and in particular to a live-line working and live-line training boosting system and method. Background Art

[0002] With continuous technological breakthroughs and innovations, live work operations and training have continued to advance. Safe and standardized live work tools and equipment have emerged, and virtual simulation live work training platforms have also developed significantly. Numerous live work training materials and technical specifications have been released, a large number of live work training bases have been put into operation, and live work assessment standards have been gradually improved, cultivating a large number of live work professionals. Current live work training includes a combination of virtual reality (VR) and augmented reality (AR), simulation equipment, online learning and assessment platforms, mixed reality (MR) and digital twins, intelligent safety tools, and traditional hands-on training. Overall, existing technologies, combining virtual reality, simulation, and hands-on training, form a step-by-step training system that significantly reduces the risks of live work training and improves training efficiency. With the continued development of artificial intelligence and the Internet of Things (IoT), live work training will become more intelligent and personalized, further ensuring the efficiency and safety of the power industry.

[0003] With the development and advancement of technology in the power industry, live-line work training has also experienced explosive growth. However, existing live-line work training technologies still have shortcomings in terms of cost control, authenticity, standardization, psychological training, and sustainability. The limitations of artificial intelligence technology and the lack of simulation equipment have reduced the practicality of live-line work training. Furthermore, the lack of safety measures in traditional hands-on training can lead to electric shock accidents and psychological barriers. Most actual training processes are "off-line," resulting in operators, after completing training assessments, experiencing distorted performance when faced with actual live-line work due to psychological fear and lack of proficiency. Traditional live-line work training is ineffective and cannot guarantee personal safety. Live-line workers face significant personal safety risks, and there is an urgent need to develop an industry-wide standardized live-line work training platform.

[0004] The present invention needs to solve the problem systematically and develop a live working and live training system to prevent personal electric shock while meeting the live working and live training requirements, thus realizing the transition of live working training from "technical assistance" to "comprehensive empowerment". Summary of the Invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: how to solve the problem that traditional live working training has poor actual effect and cannot guarantee personal safety, and there are great personal safety hazards for live working personnel.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a live working and live training boosting system, which includes a 0.4kV AC power supply, a fully controlled power electronic power switch, a power electronic power controller, a fully controlled power electronic low-voltage switch, a three-winding step-up transformer, a current sensor, a training circuit, a series reactor and a control and protection unit; the left side of the fully controlled power electronic power switch is connected to the 0.4kV AC power supply, and the right side is connected to the power electronic power controller; the right side of the power electronic power controller is connected to the three-winding step-up transformer through the fully controlled power electronic low-voltage switch; the right side of the three-winding step-up transformer is connected in series with a current sensor, and the neutral point of the three-winding step-up transformer is connected in series with a series reactor to ground; the right side of the current sensor is connected to the training circuit, and the monitored current information is transmitted to the control and protection unit; the control and protection unit controls the opening and closing of the fully controlled power electronic low-voltage switch.

[0008] As a preferred solution of the live working and live training boosting system described in the present invention, the power electronic power supply controller includes a rectifier unit, an inverter unit and a relay protection unit, and the low-voltage side voltage of the three-winding boosting transformer is adjusted to any value of 0.4kV AC power supply rated value and below through the rectifier unit and the inverter unit.

[0009] As a preferred solution of the live working and live training boosting system described in the present invention, the fully controlled power electronic power switch includes a relay protection unit of a power electronic power controller that controls the opening and closing of the fully controlled power electronic power switch.

[0010] As a preferred solution of the live working and live training boosting system described in the present invention, the control and protection unit controls the opening and closing of the fully-controlled power electronic low-voltage switch, including that the control and protection unit controls the opening and closing of the fully-controlled power electronic low-voltage switch according to the current information monitored by the current sensor.

[0011] As a preferred solution of the live working and live training boosting system described in the present invention, the three-winding boosting transformer includes a system for boosting the 0.4kV voltage of the power electronic power controller after rectification and inversion to the rated voltage level required by the training circuit; the high-voltage side and the medium-voltage side of the three-winding boosting transformer are both star-connected, and the neutral point is non-directly grounded.

[0012] As a preferred solution of the live working and live training boosting system described in the present invention, the training circuit includes a training circuit connected to a three-winding boosting transformer on the left side, a current sensor is arranged in series in the middle, and a series inductor is used for indirect grounding of the three-winding boosting transformer, and the parameters are calculated and determined based on the parameters of the training circuit, the safe electric shock current limit of the live working training personnel, and the rated parameters of the transformer.

[0013] Another object of the present invention is to provide a method for boosting voltage during live-line working and live-line training.

[0014] To solve the above technical problems, the present invention provides the following technical solutions: a method for boosting live working training, comprising: determining the connection relationship between each module; selecting the structural configuration and initial parameters of each module; establishing an equivalent topology circuit and calculating the target values ​​of the capacitance reactance and the series grounding reactance according to the training line parameters, rated voltage, selected electric shock current limit and personal resistance value; after ignoring the personal resistance, based on the electric shock current limit, capacitance reactance and rated voltage, the series reactance value is reversed through the equivalent electrical formula, and the reactance parameters of the series grounding reactor are determined, so that the current of the system does not exceed the set safety limit when an electric shock occurs.

[0015] As a preferred solution of the live working and live training boosting method described in the present invention, the selection of the structural configuration and initial parameters of each module includes determining the types and specifications of the three-winding boosting transformer, three-winding boosting transformer, training circuit and related electrical components according to the live training requirements, and completing the initial matching of the system.

[0016] As a preferred solution of the live working training boosting method described in the present invention, the method includes: determining the three-phase distributed capacitance structure and calculating the line capacitive reactance based on the cable type and laying length adopted in the training line according to the training line parameters, rated voltage, selected electric shock current limit and personal resistance value; setting the rated voltage and electric shock current limit, and establishing a mathematical model based on the equivalent circuit diagram; comprehensively considering the influence of personal resistance on loop impedance, deriving an electrical relationship expression including capacitive reactance, voltage, personal resistance and electric shock current, and guiding the calculation of the series grounding reactance value.

[0017] This preferred solution determines the three-phase distributed capacitance structure based on the cable type and length of the training circuit, and calculates the capacitive reactance accordingly, so as to obtain electrical parameters that accurately match the training working conditions; an equivalent circuit model is established by combining the rated voltage and electric shock current limit, and the human body resistance is introduced into the modeling process, so that the circuit electrical expression including various influencing factors can be obtained, so that the subsequent inductor calculation process has a clear physical basis and input parameter constraints, thereby improving the accuracy and theoretical rigor of the design scheme.

[0018] As a preferred solution of the live working training and voltage boosting method described in the present invention, the reverse deduction of the series reactance value through the equivalent electrical formula includes ignoring the human body resistance in the modeling on the basis of the known line capacitance, voltage and target current limit; using the equivalent circuit model to construct a relationship formula between the electric shock current and the series grounding reactance; substituting the line capacitance as a known quantity into the formula to obtain the reactance value expression; solving the reactance parameter range required for the series grounding reactor based on the reactance value expression, and completing the reverse determination of the component parameters.

[0019] This preferred solution constructs an equivalent circuit model that ignores the influence of human body resistance by taking the line capacitance, voltage and electric shock current limit as input, and derives the calculation formula between the electric shock current and the series grounding reactance, so that the reactance value can be obtained by reverse deduction; this method eliminates the uncertainty of manual experience setting, making the parameters of the series grounding reactor calculable, verifiable and controllable, which helps to ensure that the electric shock current under the set constraints does not exceed the limit, thereby enhancing the electrical safety control capability of the boost system.

[0020] The beneficial effects of the present invention are as follows: the present invention adjusts the AC power supply to an appropriate value through the power electronic power supply controller and sends it to the low-voltage side of the three-winding step-up transformer, and increases the voltage to the voltage required by the live working and live training platform through the step-up transformer, so that it meets the live training voltage requirements; at the same time, by designing the parameters of the boost system components, the electric shock current of any operator who is electrically shocked during training will not exceed the electric shock current limit. At the same time, the power electronic power supply controller includes a relay protection unit that can control the power switch to be turned on and off, so that the boost system meets the live training voltage level requirements while ensuring personal electric shock safety.

[0021] It meets the multiple voltage levels (10kV, 35kV) required for live-line work training, truly enabling "live" training. For practical training routes, the appropriate cable type and length can be designed to meet various live-line work training needs. The transformer's series reactance grounding limits the current of electric shock, and the control and protection unit monitors current and controls the opening and closing of the low-voltage switch, providing an additional layer of protection against electric shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a system topology diagram of a live working and live training boosting system provided by one embodiment of the present invention.

[0024] Figure 2 The present invention provides an overall flow chart of a method for boosting live working and live training according to an embodiment of the present invention.

[0025] Figure 3 A flow chart for calculating series grounding reactance parameters for a live working and live training voltage boosting method provided in one embodiment of the present invention.

[0026] Figure 4A schematic diagram of an equivalent topological circuit for calculating the electric shock current for live work training and boosting voltage provided by an embodiment of the present invention.

[0027] Figure 5 This is a 35kV simulation circuit topology diagram of a live working and live training voltage boosting method provided by one embodiment of the present invention.

[0028] Figure 6 This is a 35kV side fault current diagram of a live working and live training boosting method provided by one embodiment of the present invention.

[0029] Figure 7 This is a 10kV simulation circuit topology diagram of a live working and live training voltage boosting method provided by one embodiment of the present invention.

[0030] Figure 8 This is a 10kV side fault current diagram of a live working and live training voltage boosting method provided by one embodiment of the present invention.

[0031] In the figure: 1. 0.4kV AC power supply; 2. Fully controlled power electronic power switch; 3. Power electronic power controller; 4. Fully controlled power electronic low-voltage switch; 5. Three-winding step-up transformer; 6. Current sensor; 7. Training circuit; 8. Series reactor; 9. Control and protection unit. DETAILED DESCRIPTION

[0032] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0033] Example 1 is an embodiment of the present invention, which provides a live working and live training boosting system, including:

[0034] 0.4kV AC power supply, fully controlled power electronic power switch, power electronic power controller, fully controlled power electronic low-voltage switch, three-winding step-up transformer, current sensor, training circuit, series reactor and control and protection unit.

[0035] The left side of the fully controlled power electronic power switch is connected to a 0.4kV AC power supply, and the right side is connected to a power electronic power controller.

[0036] The right side of the power electronic power controller is connected to a three-winding step-up transformer through a fully controlled power electronic low-voltage switch.

[0037] A current sensor is connected in series on the right side of the three-winding step-up transformer, and the neutral point of the three-winding step-up transformer is connected in series with a series reactor and grounded.

[0038] The right side of the current sensor is connected to the training circuit, and the monitored current information is transmitted to the control and protection unit.

[0039] The control and protection unit controls the opening and closing of the fully controlled power electronic low-voltage switch.

[0040] This training boost system coordinates the power electronics (rectifier, inverter, and relay protection unit) power controller and a three-winding step-up transformer to ensure that the voltage level (10kV, 35kV) at the training line meets the requirements for live-line working training. Effective connections between current sensors, control and protection units, and fully controlled power electronic switches ensure the safety of live-line workers from electric shock during training. Furthermore, the three-winding step-up transformer is connected in series with a reactance grounding to effectively limit the current flowing through the training line. This ensures that the voltage level requirements for live-line working training are met while preventing electric shock.

[0041] Example 2, reference Figure 1 , which is an embodiment of the present invention, provides a live working live training boosting system based on the previous embodiment, including:

[0042] 0.4kV AC power supply 1, fully controlled power electronic power switch 2, power electronic power controller 3, fully controlled power electronic low-voltage switch 4, three-winding step-up transformer 5, current sensor 6, training circuit 7, series reactor 8, control and protection unit 9.

[0043] The power electronic power supply controller 3 includes a rectifier unit, an inverter unit and a relay protection unit, which adjusts the low-voltage side voltage of the three-winding step-up transformer 5 to any value within or below the rated value of the 0.4kV AC power supply 1 through the rectifier unit and the inverter unit.

[0044] The opening and closing of the fully controlled power electronic power switch 2 is controlled by the relay protection unit of the power electronic power controller 3 .

[0045] The control and protection unit 9 controls the opening and closing of the fully controlled power electronic low-voltage switch 4 according to the current information monitored by the current sensor 6 .

[0046] The three-winding step-up transformer 5 boosts the 0.4kV voltage of the power electronic power controller 3 after rectification and inversion to the rated voltage level required by the training circuit 7; the high-voltage side and the medium-voltage side of the three-winding step-up transformer 5 are both star-connected, and the neutral point is non-directly grounded.

[0047] The left side of the training circuit 7 is connected to the three-winding step-up transformer 5, a current sensor 6 is set in series in the middle, and the series inductor 8 is used for indirect grounding of the three-winding step-up transformer 5. The parameters are determined based on the parameters of the training circuit 7, the safe electric shock current limit for live working training personnel, and the rated parameters of the transformer.

[0048] Specifically, the left side of the power switch is connected to a 0.4kV AC power supply 1, and the right side is connected to a power electronic power controller 3. The fully controlled power electronic power switch 2 is a fully controlled power electronic device with a rated voltage within the range of 0.4kV to 1kV. The fully controlled power electronic power switch 2 is switched on and off by a protection relay unit (PRC) in the power electronic power controller 3, and its switching time is less than 1ms. The right side of the power electronic power controller 3 is connected to a three-winding step-up transformer 5. The power electronic power controller 3 includes a rectifier, an inverter, and a relay unit, which can adjust the low-voltage side voltage of the three-winding step-up transformer 5 to 100V through the rectifier and inverter units. For any value of 0.4kV AC power rating and below, the protection relay unit (PRC) controls the power switch to shut down; there is a fully controlled power electronic low-voltage switch 4 between the power electronic power controller 3 and the three-winding step-up transformer 5. The fully controlled power electronic low-voltage switch 4 is a fully controlled power electronic device with a breaking time of no more than 1ms, wherein the protection control unit 9 can control the breaking of the low-voltage switch according to the current information monitored by the current sensor; the right side of the three-winding step-up transformer is connected to the training circuit 7; the three-winding step-up transformer 5 can boost the 0.4kV voltage of the power electronic power controller after rectification and inversion to the rated voltage required by the training circuit 7 Voltage level; the high-voltage and medium-voltage sides of the three-winding step-up transformer 5 are both star-connected, and the neutral point is non-directly grounded; the left side of the current sensor 6 is connected to the three-winding step-up transformer 5, and the right side is connected to the training circuit 7. The installation position of the current sensor 6 can be selected at the outlet position of the three-winding step-up transformer 5, which is used to monitor the current output from the medium and high-voltage sides of the three-winding step-up transformer 5. The monitored current information is transmitted to the control and protection unit 9 to control the opening and closing of the fully controlled power electronic low-voltage switch 4; the left side of the training circuit 7 is connected to the three-winding step-up transformer 5, and the current sensor 6 is connected in series. The length and model of the training circuit 7 can be adjusted according to the actual training situation. The training needs are determined, and its cable parameters are also determined by the model and length; the series inductor 8 is used for the non-direct grounding of the three-winding step-up transformer 5, and its parameters can be determined according to the parameters of the live training line 7, the safe electric shock current limit of the live working training personnel, and the rated parameters of the transformer. The series inductor 8 can effectively limit the personal electric shock current, greatly improving the safety of the live training personnel; the control and protection unit 9 is used to collect the current information of the current sensor 6, and control the shutdown of the fully controlled power electronic low-voltage switch 4 by judging the current information. When the series reactor 8 of the step-up transformer is grounded, it limits the personal electric shock current and adds another layer of protection for personal electric shock.

[0049] The live working live training boosting system is required to effectively limit the electric shock current to the human body while meeting the operating voltage level of the training circuit. The present invention is connected to an external 0.4kV AC power supply 1, which is adjusted to a suitable value by the power electronic power supply controller 3 (containing AC / DC, DC / AC, and PRC units) and sent to the low-voltage side of the three-winding step-up transformer 5 for boosting to obtain the rated voltage level of the training circuit 7; wherein the personal electric shock current is limited by the grounding of the series inductor 8, and the current is monitored by the current sensor 6 connected in series at the outlet of the three-winding step-up transformer 5. After obtaining the current information through the control and protection unit 9, the fully controlled power electronic low-voltage switch 4 is controlled to be disconnected to ensure personal safety, thereby achieving boosting while ensuring personal safety.

[0050] Example 3, reference Figure 2 , is an embodiment of the present invention, which provides a live working live training boosting system, comprising:

[0051] S1. Determine the connection relationship between each module.

[0052] S2. Select the structural configuration and initial parameters of each module.

[0053] S3. Based on the training circuit parameters, rated voltage, selected electric shock current limit and human body resistance value, establish an equivalent topology circuit and calculate the target values ​​of capacitor reactance and series grounding reactance.

[0054] S4. After ignoring the human body resistance, reversely calculate the series reactance value based on the electric shock current limit, capacitor reactance and rated voltage through the equivalent electrical formula, and determine the reactance parameters of the series grounding reactor so that the current of the system does not exceed the set safety limit when an electric shock occurs.

[0055] When designing a booster system for live working and live training, after ensuring the effective connection between each module, it is also necessary to determine some component parameters. Only by selecting suitable components can the booster system be able to achieve the boosting function while ensuring personal safety.

[0056] Through the present invention, the complete process of the live working and live training boosting system is completed from module connection layout, component selection and configuration, equivalent model establishment to reactance parameter reverse design. It has a clear structural input basis, modeling path and electrical parameter solution logic, can meet the requirements of each step in the system design method being implementable and reproducible, and the steps of the process are correlated and coherent, which is suitable for the structural design and parameter configuration of the boosting system in actual live training scenarios.

[0057] Example 4, reference Figure 3 and Figure 4 , which is an embodiment of the present invention, provides a live working live training and voltage boosting method based on the previous embodiment, comprising:

[0058] In the implementation manner of the present application, the connection relationship between the modules is determined in step S1.

[0059] 0.4kV AC power supply, fully-controlled power electronic power switch, power electronic power controller, fully-controlled power electronic low-voltage switch, three-winding step-up transformer, current sensor, training circuit, series reactor and control and protection unit; the left side of the fully-controlled power electronic power switch is connected to the 0.4kV AC power supply, and the right side is connected to the power electronic power controller; the right side of the power electronic power controller is connected to the three-winding step-up transformer through the fully-controlled power electronic low-voltage switch; the right side of the three-winding step-up transformer is connected in series with a current sensor, and the neutral point of the three-winding step-up transformer is connected in series with a series reactor to ground; the right side of the current sensor is connected to the training circuit, and the monitored current information is transmitted to the control and protection unit; the control and protection unit controls the opening and closing of the fully-controlled power electronic low-voltage switch.

[0060] The boost system is connected to an external 0.4kV power supply. The fully controlled power electronic power switch, power electronic power controller, fully controlled power electronic low-voltage switch, three-winding boost transformer, current sensor, and training circuit are connected from left to right. The current sensor is placed at the outlet of the three-winding boost transformer, and the three-winding boost transformer is grounded via a series reactor.

[0061] In an optional embodiment, the current sensor adopts an embedded integrated packaging structure and is directly integrated into the inner side of the outlet bushing at the outlet end of the step-up transformer to reduce the wiring length; a voltage monitoring point is provided between the series inductor and the grounding wire to obtain the potential changes on the grounding branch in real time during system operation, and to assist the control and protection unit in making status judgments.

[0062] In another optional embodiment, an insulating platform is provided between the step-up transformer and the series inductor to form an electrical isolation area to meet the insulation coordination requirements under different voltage levels; the control and protection unit is arranged in an independent protective box and is physically isolated from the high-voltage area to meet the electrical safety requirements in a complex training environment.

[0063] The present invention can design suitable cable types and lengths according to needs, and can meet various live-line working and live-line training needs.

[0064] In the embodiment of the present application, the structural configuration and initial parameters of each module are selected in step S2.

[0065] Based on the needs of live training, determine the types and specifications of the three-winding step-up transformer, three-winding step-up transformer, training circuit and related electrical components to complete the initial matching of the system.

[0066] Specifically, select appropriate modules, and the power electronic power controller should be a multifunctional integrated device containing rectification, inversion, and relay protection units; all switches should be fully controlled power electronic devices with a breaking time of less than 1ms; the step-up transformer should be a three-winding step-up transformer, which can provide multiple voltage levels according to the training requirements; the type and length of the training line cable can be selected according to the training requirements.

[0067] In an optional embodiment, the functional units of the power electronic power controller adopt a split structure, the rectifier and inverter units are arranged in the main cabinet, and the relay protection unit is separately configured in the control and protection cabinet; the step-up transformer adopts a fixed ratio structure, and the output voltage is achieved by adjusting the input side voltage, which is suitable for teaching scenarios with fixed site voltage requirements; the training line adopts a ground trough laying method, the cable uses a multi-core shielded structure, and the length is preset to a fixed length segment, which is convenient for disassembly and repeated use.

[0068] In another optional embodiment, the selected power supply controller has a communication interface and digital adjustment function, and can be connected to an external host computer for parameter setting and switching; the step-up transformer adopts an oil-immersed structure, taking into account the long-term working condition stability requirements; the training line is a flexible cable reel structure, which is used for indoor centralized simulation training environment, and the parameter configuration is given by the standard working condition setting table.

[0069] The present invention provides multiple solutions with different structural integration levels, configuration strategies, and installation methods during the module selection process, allowing designers to flexibly combine and configure system modules according to space conditions, voltage levels, and usage scenarios, thereby improving the adaptability and implementation efficiency of the system solution.

[0070] In the embodiment of the present application, in step S3, an equivalent topology circuit is established and the target values ​​of the capacitive reactance and the series grounding reactance are calculated based on the training circuit parameters, rated voltage, selected electric shock current limit and human body resistance value.

[0071] Based on the cable type and length used in the training circuit, the three-phase distributed capacitance structure is determined and the line capacitive reactance is calculated; the rated voltage and electric shock current limit are set, and a mathematical model is established based on the equivalent circuit diagram; the influence of human body resistance on loop impedance is integrated to derive the electrical relationship expression including capacitive reactance, voltage, human body resistance and electric shock current to guide the calculation of the series grounding reactance value.

[0072] The flow chart for calculating series grounding reactance parameters is as follows: Figure 3 shown.

[0073] Specifically, determine the specific parameters of components to meet the step-up requirements while ensuring personal safety from electric shock. Select an appropriate transformer ratio so that the medium and high voltage sides of the step-up transformer meet the 10kV and 35kV voltage level requirements. Select the appropriate cable type and length based on the training requirements. Once selected, the training circuit parameters will be determined. The transformer's series grounding reactance value will be calculated based on the human resistance and the electric shock current limit to ensure that the electric shock current does not exceed the limit.

[0074]

[0075] Among them, I h is the electric shock current, U N is the rated voltage, and the capacitive reactance of the training circuit is X C , the series grounding reactance is X L , the human body resistance is R h .

[0076] In an embodiment of the present application, after ignoring the human body resistance in step S4, the series reactance value is reversed through the equivalent electrical formula based on the electric shock current limit, capacitor reactance and rated voltage, and the reactance parameters of the series grounding reactor are determined, so that the current of the system does not exceed the set safety limit when an electric shock occurs.

[0077] The equivalent topological circuit diagram for calculating the current of electric shock to human body is as follows Figure 4 shown.

[0078] Based on the known line capacitance, voltage and target current limit, the human body resistance is ignored in the modeling; an equivalent circuit model is used to construct the relationship formula between the electric shock current and the series grounding reactance; the line capacitance is substituted into the formula as a known quantity to obtain the reactance value expression; based on the reactance value expression, the required reactance parameter range of the series grounding reactor is solved, and the reverse determination of the component parameters is completed.

[0079] Specifically, after selecting the electric shock current limit, determining the training circuit parameters, and determining the human body resistance, the size of the transformer series reactance can be reversely calculated based on the rated voltage.

[0080] Ignoring the human body resistance:

[0081]

[0082] The cable type for the training line is 1km long JL / G1A-240 / 30 steel core aluminum stranded overhead cable. The parallel capacitance of the three-phase distributed capacitance to ground is -j192kΩ and the modulus is 192kΩ. The human body resistance range is set to 1kΩ~3kΩ, and the electric shock current range is set to 100mA~150mA. Figure 3It can be seen that the greater the human body resistance, the smaller the electric shock current. Therefore, in the actual calculation process, the human body resistance is ignored and the electric shock current in extreme cases is calculated.

[0083] When the electric shock current limit is selected as 150mA, the calculated reactance value is XL=450jkΩ, and the modulus is 450kΩ. Therefore, when the series reactance is greater than or equal to the above value, the electric shock current of a person in the training circuit will not exceed 150mA.

[0084] Example 5, reference Figures 5 to 8 , which is an embodiment of the present invention, provides a method for boosting voltage during live working and live training. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0085] The experimental simulation model was built in PSCAD for verification. The three-phase power supply output voltage was used, the input voltage was the frequency f = 50Hz, and the line voltage U in =400V AC mains, select a three-winding transformer with two output voltage levels of 10 and 35kV, and coordinate the series reactance by the size of the capacitance to ground to limit the personal electric shock fault current.

[0086] 35kV side verification:

[0087] In the simulation verification, the 35kV side of the transformer was selected as an example, and the human body resistance range was set to 1kΩ~3kΩ. The cable-to-ground capacitance value was estimated based on the cable type, length, and installation height to the ground. A 1000-meter-long JL / G1A-240 / 30 steel-core aluminum stranded wire overhead cable was selected and installed at a height of 10 meters to the ground. Its capacitance to the ground was approximately 0.004uF, and the series grounding reactance value was set to 1000H.

[0088]

[0089] Among them, ∈0 is the dielectric constant of vacuum, which is approximately 8.854×10-12F / m; π is the pi, D is the effective distance from the wire to the ground (10 meters); r is the radius of the wire, and the equivalent radius is 3.63mm; L is the line length.

[0090] Build the model in PSCAD, setting the human shock resistance to 3000Ω. Assume a human shock occurs on phase A of the 35kV training line. Set the fault to occur after 0.5s, and the entire process to run for 1s. Compile the program based on these parameter settings to verify whether the fault current exceeds the human shock current limit. The simulation parameter settings for the 35kV side are shown in Table 1.

[0091] Table 135kV side simulation parameter settings

[0092]

[0093]

[0094] Depend on Figure 5 and Figure 6 It can be seen from the figure that when the fault occurs at 0.5s, the current suddenly changes, and the fault current begins to stabilize over time. The peak value of the fault current does not exceed 150mA. After stabilizing, it is around 120mA, which does not exceed the given limit of 150mA. It can be seen that the grounding reactor with a series value of 1000H on the 35kV side of the transformer can effectively limit the fault current within the limit range.

[0095] 10kV side verification:

[0096] In the simulation verification, the 10kV side of the transformer is selected as an example. The human body resistance range is set to 1kΩ~3kΩ. The cable-to-ground capacitance value is estimated based on the cable type, length, and installation height to the ground. A 1000-meter-long JL / G1A-240 / 30 steel-core aluminum stranded wire overhead cable is selected and installed at a height of 10 meters to the ground. Its capacitance to the ground can be calculated, and the series grounding reactance value is set to 1000H.

[0097]

[0098] Where ∈0 is the dielectric constant of a vacuum, approximately 8.854×10⁻¹² F / m; D is the effective distance from the conductor to the ground (10 meters); r is the radius of the conductor, equivalent to 3.63 mm; and L is the line length. Calculated capacitance to ground is approximately 0.004 µF.

[0099] Table 2 10kV side simulation parameter settings

[0100] Parameter Value f 50Hz <![CDATA[U in ]]> 0.4kV <![CDATA[U o ]]> 10kV C 0.004uF L 1000H <![CDATA[R gz ]]> 1kΩ

[0101] Build the model in PSCAD, setting the human shock resistance to 1000Ω. Assume that a person is electrocuted on Phase A of the 10kV training line. Set the fault to occur after 0.5s, and the entire process to run for 1s. Compile the model based on the above parameter settings, as shown in Table 2, 10kV Side Simulation Parameter Settings, and verify whether the fault current exceeds the human shock current limit.

[0102] Depend on Figure 7 and Figure 8 It can be seen from the figure that when the fault occurs at 0.5s, the current suddenly changes, and the fault current begins to stabilize over time. The peak value of the fault current does not exceed 45mA, and after stabilizing, it is around 35mA, which does not exceed the given limit of 150mA. It can be seen that the grounding reactor with a series value of 1000H on the 10kV side of the transformer can effectively limit the fault current within the limit range.

Claims

1. A live working and live training boosting system, characterized by: include, 0.4kV AC power supply, fully controlled power electronic power switch, power electronic power controller, fully controlled power electronic low-voltage switch, three-winding step-up transformer, current sensor, training circuit, series reactor and control and protection unit; The left side of the fully controlled power electronic power switch is connected to a 0.4kV AC power supply, and the right side is connected to a power electronic power controller; The right side of the power electronic power controller is connected to a three-winding step-up transformer through a fully controlled power electronic low-voltage switch; A current sensor is connected in series on the right side of the three-winding step-up transformer, and the neutral point of the three-winding step-up transformer is connected in series with a series reactor to ground; The right side of the current sensor is connected to the training circuit, and the monitored current information is transmitted to the control and protection unit; The control and protection unit controls the opening and closing of the fully controlled power electronic low-voltage switch.

2. A live working live training boosting system according to claim 1, characterized in that: The power electronic power supply controller includes a rectifier unit, an inverter unit and a relay protection unit, and adjusts the low-voltage side voltage of the three-winding step-up transformer to any value within or below the rated value of the 0.4kV AC power supply through the rectifier unit and the inverter unit.

3. A live working live training boosting system as claimed in claim 2, characterized in that: The fully controlled power electronic power switch includes controlling the opening and closing of the fully controlled power electronic power switch through a relay protection unit of a power electronic power controller.

4. A live working live training boosting system as claimed in claim 3, characterized in that: The control and protection unit controls the opening and closing of the fully controlled power electronic low-voltage switch, including: The control and protection unit controls the opening and closing of the fully controlled power electronic low-voltage switch according to the current information monitored by the current sensor.

5. The live working and live training boosting system according to claim 4, characterized in that: The three-winding step-up transformer includes a device for stepping up the 0.4kV voltage of the power electronic power controller after rectification and inversion to the rated voltage level required by the training circuit; The high-voltage side and medium-voltage side of the three-winding step-up transformer are both star-connected, and the neutral point is non-directly grounded.

6. A live working live training boosting system according to claim 4, characterized in that: The training circuit includes a connection with a three-winding step-up transformer on the left side of the training circuit, a current sensor is set in series in the middle, and a series inductor is used for indirect grounding of the three-winding step-up transformer. The parameters are determined based on the parameters of the training circuit, the safe electric shock current limit of live working training personnel, and the rated parameters of the transformer.

7. A method for boosting voltage for live working and live training, using a system for boosting voltage for live working and live training as claimed in any one of claims 1 to 6, characterized in that: include: Determine the connection relationship between each module; Select the structural configuration and initial parameters of each module; Based on the training circuit parameters, rated voltage, selected electric shock current limit and human body resistance value, establish an equivalent topology circuit and calculate the target values ​​of capacitance reactance and series grounding reactance; After ignoring the human body resistance, the series reactance value is reversed through the equivalent electrical formula based on the electric shock current limit, capacitor reactance and rated voltage, and the reactance parameters of the series grounding reactor are determined so that the current of the system does not exceed the set safety limit when an electric shock occurs.

8. A method for boosting voltage in live working training according to claim 7, characterized in that: The selection of the structural configuration and initial parameters of each module includes determining the types and specifications of the three-winding step-up transformer, the three-winding step-up transformer, the training circuit and related electrical components according to the needs of live training, and completing the initial matching of the system.

9. A method for boosting voltage during live working training according to claim 8, characterized in that: The training circuit parameters, rated voltage, selected electric shock current limit and human body resistance value include: Determine the three-phase distributed capacitance structure and calculate the line capacitive reactance based on the cable type and length used in the training circuit; Set the rated voltage and electric shock current limit, and establish a mathematical model based on the equivalent circuit diagram; Taking into account the influence of human body resistance on loop impedance, the electrical relationship expression including capacitive reactance, voltage, human body resistance and electric shock current is derived to guide the calculation of series grounding reactance value.

10. A method for boosting voltage in live working training according to claim 9, characterized in that: The reverse calculation of the series reactance value by the equivalent electrical formula includes ignoring the human body resistance in the modeling based on the known line capacitance, voltage and target current limit; Using the equivalent circuit model, the relationship formula between electric shock current and series grounding reactance is constructed; Substituting the line capacitive reactance as a known quantity into the formula, we can obtain the reactance value expression; According to the reactance value expression, the required reactance parameter range of the series grounding reactor is solved, and the reverse determination of the component parameters is completed.

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