CN111426983A - Single-phase earth fault positioning system of power distribution overhead cable hybrid line - Google Patents

Abstract

The invention relates to a single-phase grounding fault location system of a power distribution overhead cable hybrid line. Including a small current line selection device, the small current line selection device includes a voltage component that obtains three-phase voltage or zero-sequence voltage and a current component that obtains three-phase current or zero-sequence current, and the low-current line selection device also includes a transformer module, zero sequence A current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and a wireless communication module; it also includes a positioning device, and the positioning device includes a voltage component for obtaining three-phase voltage or zero-sequence voltage, and A current component for acquiring three-phase current or zero-sequence current, and the positioning device also includes a transformer module, a zero-sequence current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and wireless communication module; also includes the background management host. The invention improves the accuracy and rapidity of the location of the one-way grounding fault of the distribution line.

Description

A single-phase grounding fault location system for distribution overhead cable hybrid line

technical field

The invention belongs to the technical field of power transmission and distribution fault detection, and in particular relates to a single-phase grounding fault location system of a power distribution overhead cable hybrid line.

Background technique

The distribution network usually refers to the power grid with a voltage level of 110KV and below, which is responsible for the function of directly supplying power to users in the power system. The reliability of power supply from the distribution network directly affects the safety and economy of users' electricity consumption. According to statistics, more than 95% of the power outages suffered by power users are caused by the distribution system, and about half of the power system losses are generated in the distribution network. In recent years, with the development of the national economy, the electricity load has increased significantly. In some areas, due to the fact that the construction of the distribution network cannot keep up with the growth of the electricity load level, there have been phenomena such as power outages and frequent failures. At the same time, users have higher and higher requirements for power quality. Both power grid dispatchers and users are eager to quantify the safety and economy of power supply in the distribution network, so as to improve the accuracy of the dispatcher's decision-making and the intelligence level of the distribution network. Research on the distribution network risk assessment and early warning technology before the fault, the rapid fault location technology during the fault process and the distribution network fault diagnosis technology after the fault have important theoretical research significance and engineering practice value for the current intelligent construction of the distribution network.

The problem of single-phase grounding fault location has plagued the operation department for a long time. At present, the on-site staff often determine the fault section by the test-pull method, that is, first disconnect the outgoing circuit breaker of the faulty line in the substation, and then disconnect the section switch in the middle of the line , and finally reclose the outgoing circuit breaker of the substation. If there is no fault, it means that the fault point is behind the sectional switch, and so on. Every opening and closing of the switch will have an impact on the power grid, and it is easy to generate operating overvoltage and resonance overvoltage, and frequent switching operations will also reduce the service life of the switch. For unattended substations, remote remote control is required, which increases the burden of equipment. Therefore, fast and accurate fault location technology is conducive to maintaining power grid equipment, improving the service life of equipment, and reducing maintenance and repair burdens.

To sum up, the single-phase grounding fault location technology of small current grounding system can improve the reliability of power supply, improve the economic benefits of power supply departments and users, and maintain power grid equipment, which is of great significance. The implementation of distribution automation is the fundamental guarantee to solve the current problems in the distribution network, and distribution network fault location is one of the key technologies of distribution automation. economical and reliable operation plays an important role. However, there are various methods of fault location, and the location results obtained are different. Therefore, it is necessary to study the method of fault handling performance test of distribution network to ensure the accuracy of fault location, not only to ensure the safe, stable and economical operation of the power grid, but also to Moreover, it is helpful for the popularization and use of new energy technology in the power system, which can improve the social and economic benefits of the power supply department and users, and is of great significance to the safe production of the power system.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the known technology, the present invention provides a single-phase grounding fault location system of a distribution overhead cable hybrid line with a reasonable structure design, and improves the accuracy and rapidity of the one-way grounding fault location of the distribution line.

The technical scheme adopted in the present invention is:

A single-phase grounding fault location system for power distribution overhead cable hybrid line, including a low-current line selection device arranged in a substation, the low-current line selection device including a power distribution bus of the substation for obtaining three-phase voltage or zero. The voltage component of the sequence voltage and the current component set on the distribution branch line to obtain the three-phase current or the zero-sequence current at the position, the small current line selection device also includes a transformer module, a zero-sequence current acquisition module, and a current/voltage conversion module, analog-to-digital conversion module, data processing module, controller module, power supply module and wireless communication module, the output terminal of the zero-sequence current acquisition module is connected to the input terminal of the current/voltage conversion module, and the transformer module is connected to the current/voltage conversion module The output ends of the two are connected with the analog-to-digital conversion module, the output end of the analog-to-digital conversion module is connected with the input end of the data processing module, the data processing module, the power supply module and the wireless communication module are all connected with the controller module, and the output end of the voltage component It is connected to the input end of the transformer module, and the output end of the current component is connected to the input end of the zero-sequence current acquisition module; it also includes a positioning device arranged on each pole of the distribution branch line, and the positioning device includes a positioning device arranged on the distribution line. A voltage component for acquiring three-phase voltage or zero-sequence voltage and a current component for acquiring three-phase current or zero-sequence current, the positioning device further includes a transformer module, a zero-sequence current acquisition module, a current/voltage conversion module, and a modulus The conversion module, the data processing module, the controller module, the power supply module and the wireless communication module, the output terminal of the zero-sequence current acquisition module is connected with the input terminal of the current/voltage conversion module, and the outputs of both the voltage conversion module and the current/voltage conversion module The terminal is connected to the analog-to-digital conversion module, the output terminal of the analog-to-digital conversion module is connected to the input terminal of the data processing module, the data processing module, the power supply module and the wireless communication module are all connected to the controller module, and the output terminal of the voltage component is connected to the transformer The input end of the module and the output end of the current component are connected to the input end of the zero-sequence current acquisition module; it also includes a background management host, and each small current line selection device and each positioning device are connected to the background management host through their respective wireless communication modules. .

Further, the voltage component of the small current line selection device is a voltage transformer, and the current component is three current transformers and a zero-sequence current transformer that are respectively arranged on each phase line; the voltage component of the positioning device is a voltage Transformer, the current component is an intelligent circuit breaker.

Further, the power supply module of the low-current line selection device directly obtains electrical energy from the power supply facility of the substation, including a voltage converter; the power supply module of the positioning device includes a rechargeable battery that obtains electrical energy from a voltage transformer, and also includes a battery management circuit. .

Further, the voltage transformers of each small current line selection device and each positioning device are selected as three-phase five-column voltage transformers.

Further, the background management host has built-in master station software; the master station software includes a data processing module for processing data transmitted by each small current line selection device and each positioning device, and the master station software also includes a positioning module for processing results according to the data. Determine the location of the one-way ground fault.

The advantages and positive effects of the present invention are:

1. In the present invention, by arranging a small current line selection device with voltage components and current components on the distribution bus of the substation, the acquisition of three-phase voltage and zero-sequence voltage on the distribution bus and the The acquisition of three-phase current and zero-sequence current, through comprehensive calculation with the above three-phase current, zero-sequence current, three-phase voltage and zero-sequence voltage as parameters, realizes the line selection operation of the fault line.

2. By setting voltage components and current components on the poles of the distribution branch, the purpose of multi-point three-phase voltage, zero-sequence voltage, three-phase current and zero-sequence current on the distribution branch is realized. The comprehensive calculation of current, zero-sequence current, three-phase voltage and zero-sequence voltage as parameters realizes the judgment of the location of the one-way grounding fault. The judged one-way grounding fault point is located between two adjacent poles on the distribution branch. Therefore, the relatively precise location of the fault location is realized, and it is easier to deal with the fault in time.

3. By setting the background management host and each small current line selection device and positioning device are wirelessly connected to the background management host, the automatic processing of the above fault judgment process is realized, and the fault location process is faster.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the structural block diagram of the installation state of the small current line selection device in Fig. 1;

Fig. 3 is the installation state structural block diagram of the positioning device in Fig. 1;

In the picture: 1- Small current wire selection device, 2- Positioning device, 3- Line pole, 4- Background management host.

Detailed ways

In order to further understand the content of the invention, features and effects of the present invention, the following examples are hereby described in detail as follows:

As shown in FIGS. 1 to 3 , the single-phase grounding fault location system for a power distribution overhead cable hybrid line of the present invention includes a low-current line selection device 1 arranged in a substation, and the low-current line selection device 1 includes a power distribution device arranged in the substation. The voltage component on the busbar for obtaining the three-phase voltage or the zero-sequence voltage and the current component on the distribution branch line for obtaining the three-phase current or the zero-sequence current at the location.

In this embodiment, the voltage components of the low-current line selection device 1 are voltage transformers, and the current components are three current transformers and one zero-sequence current transformer respectively arranged on each phase line. Further, the voltage transformer is selected as a three-phase five-column voltage transformer. Among them, the voltage transformer is used to obtain the phase voltage and zero-sequence voltage of the three phase lines of the distribution bus, and the three current transformers are respectively installed on the three phase lines of the distribution branch to obtain the phase currents on the three phase lines. The sequence current transformer is used to obtain the zero-sequence current on the distribution branch line, and the phase currents on the three phase lines can also be synthesized to obtain the zero-sequence current.

The low-current line selection device 1 also includes a transformer module, a zero-sequence current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and a wireless communication module. The output terminal is connected with the input terminal of the current/voltage conversion module, the output terminals of the voltage conversion module and the current/voltage conversion module are connected with the analog-to-digital conversion module, and the output terminal of the analog-digital conversion module is connected with the input terminal of the data processing module, The data processing module, the power supply module and the wireless communication module are all connected to the controller module, the output end of the voltage component is connected to the input end of the transformer module, and the output end of the current component is connected to the input end of the zero-sequence current acquisition module.

The above-mentioned transformer module, zero-sequence current acquisition module, current/voltage conversion module, analog-to-digital conversion module, data processing module, controller module, power supply module and wireless communication module are packaged in a casing to form an integrated device. Wiring ports are set on the shell of the equipment. The voltage components are voltage transformers, the current components are three current transformers and a zero-sequence current transformer are connected to the corresponding wiring ports through wiring terminals and lead wires for signal transmission. enter.

The voltage component, that is, the voltage transformer, obtains the phase voltage and zero-sequence voltage from each phase line. The above-mentioned voltage signals are output to the transformer module, and the low-voltage signal formed by the step-down/filtering process of the transformer module is sent to the analog-to-digital conversion module. The analog-to-digital conversion is performed to form a digitized signal, and the digitized signal enters the data processing module for data processing and calculation. The current components are three current transformers and a zero-sequence current transformer to obtain phase current and zero-sequence current from each phase line. The above current signals are output to the zero-sequence current acquisition module to obtain the final zero-sequence current. The zero-sequence current signal The current/voltage conversion module is converted into a voltage signal, and the converted voltage signal is sent to the analog-to-digital conversion module for analog-to-digital conversion to form a digitized signal, which enters the data processing module for data processing and calculation.

The controller module transmits the above-mentioned signals and the results of preliminary processing and calculation through the wireless communication module.

The power supply module provides power for the entire low-current line selection device 1. Since the low-current line selection device 1 is installed in the cabinet of the substation and there are usually power supply facilities in the substation, the power module of the low-current line selection device 1 is powered by the power supply facilities of the substation. Electric energy is directly obtained, including a voltage converter, which is used to transform the power supply provided by the power supply facility of the substation to a voltage value accepted by the low-current line selection device 1 .

It also includes a positioning device 2 arranged on each pole 3 of the distribution branch line. The positioning device 2 includes a voltage component arranged on the distribution line for obtaining three-phase voltage or zero-sequence voltage and a voltage component for obtaining three-phase current or zero-sequence voltage. The current component of the sequence current.

In this embodiment, the voltage component of the positioning device 2 is a voltage transformer, and the current component is an intelligent circuit breaker. Further, the voltage transformer is selected as a three-phase five-column voltage transformer. Among them, the intelligent circuit breaker is an existing component, which is mainly used to control and protect the low-voltage power distribution network, and is generally installed and configured on each pole 3 of the power distribution branch line. The basic working mode of the intelligent circuit breaker is to automatically select the operating mechanism and the preset working conditions of the arc extinguishing chamber according to the different fault currents detected. Open at higher speeds for optimum opening in electrical and mechanical performance. The working process of the intelligent circuit breaker is: when the system fails, the relay protection device sends an opening signal or the operator sends an operation signal, firstly start the intelligent identification module to work, judge the current working conditions of the circuit breaker, and send a signal to the adjustment device. According to different quantitative control information, the parameters of the operating mechanism are automatically adjusted to obtain the motion characteristics suitable for the current system working state, and then the circuit breaker is activated.

Among them, the voltage transformer is used to obtain the phase voltage and zero-sequence voltage of the three phase lines of the distribution line, and the phase current and zero-sequence current of the three phase lines are directly obtained through the intelligent circuit breaker.

The positioning device 2 also includes a transformer module, a zero-sequence current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and a wireless communication module. The output end of the zero-sequence current acquisition module is connected to the The input end of the current/voltage conversion module is connected, the output end of the transformer module and the current/voltage conversion module is connected with the analog-digital conversion module, the output end of the analog-digital conversion module is connected with the input end of the data processing module, and the data processing module , the power supply module and the wireless communication module are all connected with the controller module, the output end of the voltage component is connected to the input end of the transformer module, and the output end of the current component is connected to the input end of the zero-sequence current acquisition module.

The above-mentioned transformer module, zero-sequence current acquisition module, current/voltage conversion module, analog-to-digital conversion module, data processing module, controller module, power supply module and wireless communication module are packaged in a casing to form an integrated device. Wiring ports are set on the shell of the equipment, and the voltage components, namely the voltage transformers, and the current components, namely the intelligent circuit breakers, are connected to the corresponding wiring ports through the wiring terminals and lead wires for signal input.

The voltage component, that is, the voltage transformer, obtains the phase voltage and zero-sequence voltage from each phase line. The above-mentioned voltage signals are output to the transformer module, and the low-voltage signal formed by the step-down/filtering process of the transformer module is sent to the analog-to-digital conversion module. The analog-to-digital conversion is performed to form a digitized signal, and the digitized signal enters the data processing module for data processing and calculation. The current component, that is, the intelligent circuit breaker, obtains the phase current and zero-sequence current from each phase line. The above current signal is output to the zero-sequence current acquisition module to obtain the final zero-sequence current. The zero-sequence current signal enters the current/voltage conversion module and is converted into voltage. The converted voltage signal is sent to the analog-to-digital conversion module for analog-to-digital conversion to form a digitized signal, and the digitized signal enters the data processing module for data processing and calculation.

The controller module transmits the above-mentioned signals and the results of preliminary processing and calculation through the wireless communication module.

The power supply module provides power for the entire positioning device 2. Since the positioning device 2 is installed on the line pole 3, and there is usually no power supply facility on the line pole 3, the power supply module of the positioning device 2 includes a rechargeable battery that obtains power from a voltage transformer, and also Including a battery management circuit, the voltage transformer obtains electric energy by means of induction, and the electric energy is sent to the rechargeable battery for storage and use.

It also includes a background management host 4, and each low-current line selection device 1 and each positioning device 2 are connected to the background management host 4 for communication through their respective wireless communication modules.

The background management host 4 has a built-in master station software; the master station software includes a data processing module for processing the data transmitted by each small current line selection device 1 and each positioning device 2, and the master station software also includes a positioning module for determining according to the data processing results. Location of one-way ground faults. The data processing module has a built-in data processing algorithm, which performs comprehensive calculation with the above three-phase current, zero-sequence current, three-phase voltage and zero-sequence voltage as parameters to realize the judgment of one-way ground faults. Judgment of the phase-to-ground fault location, the above-mentioned single-phase-to-ground fault location is located between the two adjacent poles 3 on the distribution branch line. After the fault is located, check and maintain the line between the two poles 3. Perform accurate troubleshooting and maintenance on the location of the fault point.

Claims (5)

1. The utility model provides a single-phase earth fault positioning system of distribution overhead cable hybrid line which characterized in that: the low-current line selection device comprises a voltage component which is arranged on a distribution bus of the transformer substation and used for acquiring three-phase voltage or zero-sequence voltage, and a current component which is arranged on a distribution branch line and used for acquiring three-phase current or zero-sequence current of the position, and also comprises a voltage transformation module, a zero-sequence current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and a wireless communication module, wherein the output end of the zero-sequence current acquisition module is connected with the input end of the current/voltage conversion module, the output ends of the voltage transformation module and the current/voltage conversion module are connected with the analog-to-digital conversion module, the output end of the analog-to-digital conversion module is connected with the input end of the data processing module, and the data processing module, the power supply module and the wireless communication module, the output end of the voltage component is connected to the input end of the voltage transformation module, and the output end of the current component is connected to the input end of the zero sequence current acquisition module; the positioning device comprises a voltage component which is arranged on a distribution line and used for acquiring three-phase voltage or zero-sequence voltage and a current component which is arranged on the distribution line and used for acquiring three-phase current or zero-sequence current, a voltage transformation module, a zero-sequence current acquisition module, a current/voltage conversion module, an analog-to-digital conversion module, a data processing module, a controller module, a power supply module and a wireless communication module, wherein the output end of the zero-sequence current acquisition module is connected with the input end of the current/voltage conversion module, the output ends of the voltage transformation module and the current/voltage conversion module are connected with the analog-to-digital conversion module, the output end of the analog-to-digital conversion module is connected with the input end of the data processing module, the power supply module and the wireless communication module are all connected with the controller module, and the output end of the, the output end of the current component is connected to the input end of the zero sequence current acquisition module; the low-current line selection device and the positioning devices are in communication connection with the background management host through respective wireless communication modules.

2. The power distribution overhead cable hybrid line single phase ground fault location system of claim 1, wherein: the voltage components of the small current line selection device are voltage transformers, and the current components are three current transformers and a zero sequence current transformer which are respectively arranged on each phase line; the voltage component of the positioning device is a voltage transformer, and the current component is an intelligent circuit breaker.

3. The power distribution overhead cable hybrid line single phase ground fault location system of claim 1, wherein: the power module of the low-current line selection device directly obtains electric energy from a power supply facility of a transformer substation and comprises a voltage converter; the power module of the positioning device comprises a rechargeable battery and a storage battery management circuit, wherein the rechargeable battery is powered by a voltage transformer.

4. The power distribution overhead cable hybrid line single phase ground fault location system of claim 1, wherein: and the voltage transformers of the small current line selection devices and the positioning devices are selected to be three-phase five-column voltage transformers.

5. The power distribution overhead cable hybrid line single phase ground fault location system of claim 1, wherein: a master station software is arranged in the background management host; the main station software comprises a data processing module for processing data transmitted by each small-current line selection device and each positioning device, and a positioning module for determining the position of the one-way ground fault according to the data processing result.

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