CN213581299U - Low-voltage distribution network fault indicator - Google Patents

Abstract

The utility model provides a low-voltage distribution network fault indicator, which structurally comprises a shell part, a fixing device and an internal measurement and control unit; wherein the upper half part of the shell part is made of cylindrical opaque plastic material, and the lower half part is made of hemispherical transparent plastic material; the internal measurement and control unit is installed inside the outer shell part, the fixing device is installed at the bottom of the outer shell part and made of metal, and the internal measurement and control unit is fixed on a cable or an overhead line by adopting a screw fixing structure and a spring support. The utility model aims at the technical characteristics and the electric power parameter characteristics of the low-voltage distribution network, and further improves the action accuracy of the fault indicator on the premise of ensuring the basic performance; on the premise of combining cost and economic benefit, the fault accuracy of the fault indicator special for the low-voltage distribution network is improved to 99% from 97%.

Description

Low-voltage distribution network fault indicator

Technical Field

The utility model relates to a low voltage network fault indicator belongs to circuit check out test set technical field.

Background

The distribution network is a power network which receives electric energy from a transmission network or a regional power plant, distributes the electric energy to various users on site through distribution facilities or distributes the electric energy to various users step by step according to voltage, and consists of overhead lines, cables, towers, distribution transformers, isolating switches, reactive power compensators, auxiliary facilities and the like, and plays a role in distributing the electric energy in the power network. According to the classification of the voltage grades of the power distribution networks in China, the voltage grades are mainly divided into extra-high voltage (1000 kV alternating current and above and +/-800 kV direct current), extra-high voltage (330 kV and above to below 1000 kV), high voltage power distribution networks (35-220 kV), medium voltage power distribution networks (6-20 kV) and low voltage power distribution networks (0.4 kV). As main physical equipment in the power transmission link of a power grid, a power transmission line is the most huge component of a power system, the power transmission line has severe operating environment, complex terrain and difficult maintenance, and has important influence on the safety and reliability of the power system. Therefore, in a ring network distribution system, especially a system using a large number of ring network load switches, if a short-circuit fault or a ground fault occurs in a next-stage distribution network system, a power supply system of a previous stage must be disconnected within a specified time to prevent a major accident from occurring.

The fault indicator is used for detecting and identifying whether a power line has a fault or not, and the working principle of the fault indicator is that when the power line has faults such as short circuit, grounding and the like, due to the fact that electrical parameters in the line change suddenly, magnetic fields and electric fields are generated around the power line, a control line inside the power line fault indicator automatically detects and judges fault states, fault sections, branches and fault points are determined, then an alarm signal is output to drive a display part to work, and red is displayed in an alarm mode, so that the purpose of indicating the fault line is achieved, and inspection workers can conveniently repair and maintain the line. At present, the most easily-occurred faults in power network transmission are grounding short circuit and interphase short circuit, and the design of fault indicators is mostly based on the faults. When the phases are short-circuited, three phases or two phases of the power distribution network transmission line are contacted with each other, so that the line short circuit is broken down. When an interphase short circuit occurs, instantaneous current in a line suddenly increases to form a current jump, a sensor in the fault indicator senses a current sudden change value, and the display displays a corresponding fault signal according to the sudden change value. The criterion for single-phase earth faults is, for the moment, the most used is the zero-sequence current amplitude method.

At present, the existing fault indicator in the domestic market generally adopts a fifth harmonic detection method or a first half wave detection method. The principle of the fifth harmonic detection method is as follows: when the line is grounded, firstly, the voltage of a grounded phase is reduced, in addition, due to the grounding, a virtual capacitor formed between the overhead line and the ground is broken down, fifth harmonic components in the line are changed, and when the two conditions are met within a certain time range, the indicator considers that the line is grounded and starts to act. The principle of the first half-wave detection method is as follows: when the line is grounded, the voltage of the same grounding phase is reduced; in addition, the dummy capacitance is broken down. The difference is that the sampled data are different, the first half wave detection principle is to detect the direct current component of the transient current at the moment of capacitor breakdown, the capacitor current at the moment of grounding is sampled and compared with the voltage first half wave at the moment of grounding, when the capacitor current at the moment of grounding suddenly changes and is larger than a certain value and is in phase with the voltage first half wave at the moment of grounding, and meanwhile, the voltage of the grounding phase is reduced, the grounding is judged, otherwise, the grounding is not generated.

However, the two detection modes need to acquire current and voltage data through a current sensor and a voltage sensor, and analyze and judge the current and voltage waveforms through a microcircuit, so that the function of fault indication is realized. Due to the adoption of more modules, the production and manufacturing cost of the fault indicator is very high; meanwhile, the detection amount of the module is large, the analysis task is heavy, the response rate of the fault indicator is lowered, and the adaptability is poor. Although the fault indicator in the existing market can be suitable for the medium-voltage and high-voltage distribution network environment with detailed fault analysis requirements, the existing fault indicator obviously cannot meet the requirements of ultra-large batch and high-speed response for the low-voltage distribution network environment.

Disclosure of Invention

The utility model aims to provide a fault indicator suitable for low-voltage distribution network environment's low cost, high rate of accuracy to the above-mentioned defect that fault indicator structure and detection method in the existing market exist.

The technical solution of the utility model is as follows: a low-voltage distribution network fault indicator structurally comprises a shell part, a fixing device and an internal measurement and control unit; wherein the upper half part of the shell part is made of cylindrical opaque plastic material, and the lower half part is made of hemispherical transparent plastic material; the internal measurement and control unit is installed inside the outer shell part, the fixing device is installed at the bottom of the outer shell part and made of metal, and the internal measurement and control unit is fixed on a cable or an overhead line by adopting a screw fixing structure and a spring support.

Furthermore, the internal measurement and control unit comprises a power supply module, a current detection module, a voltage detection module, a communication module, a fault indication module and a core control module; the current detection module consists of a current sensor and an analog-to-digital converter, the voltage detection module consists of a voltage sensor and an analog-to-digital converter, the output end of the current detection module and the output end of the voltage detection module are simultaneously connected with the detection data input end of the core control module, the fault indication output end of the core control module is connected with the input end of the fault indication module, and the fault indication module consists of a signal receiving unit and an LED lamp indication unit; the fault signal output end of the core control module is connected with the input end of the communication module; the power module directly supplies power for the core control module and the fault indication module, and the core control module supplies power for the current detection module, the voltage detection module and the communication module.

Compared with the prior art, the utility model discloses following beneficial effect has: aiming at the technical characteristics and electric parameter characteristics of the low-voltage distribution network, the action accuracy of the fault indicator is further improved on the premise of ensuring the basic performance; on the premise of combining cost and economic benefit, the fault accuracy of the fault indicator special for the low-voltage distribution network is improved to 99% from 97%.

Drawings

Fig. 1 is the utility model discloses the inside measurement and control unit's of low voltage distribution network fault indicator structural schematic.

Fig. 2 is the signal processing flow chart of the low-voltage distribution network fault indicator of the utility model.

Fig. 3 is the shell structure schematic diagram of the low voltage distribution network fault indicator of the present invention.

Detailed Description

The technical scheme of the utility model is further explained in the following with the attached drawings. Examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", etc. indicate the directions or positional relationships based on the directions or positional relationships shown in the drawings, which are only for convenience of description of the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific direction and be constructed and operated in a specific direction, and thus, should not be construed as limiting the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as meaning a fixed connection, a removable connection, or an integral part; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Fig. 1 shows a fault indicator for a low-voltage distribution network, which comprises a shell part, a fixing device and an internal measurement and control unit; the internal measurement and control unit comprises a power supply module, a current detection module, a voltage detection module, a communication module, a fault indication module and a core control module, wherein the output end of the current detection module and the output end of the voltage detection module are simultaneously connected with the detection data input end of the core control module; and the power supply module is simultaneously connected with the core control module and the fault indication module and supplies power.

The core control module adopts a main control chip which is a CC2530 processing chip produced by TI company; the power module adopts a 12V solar panel; the current detection module adopts an alternating current detection module produced by the company of logele; the voltage detection module adopts KXT9U voltage induction device; the fault indication module consists of an execution circuit and an LED lamp, the execution circuit controls the on-off of the LED through an AO4606 switching tube, and the LED uses a 1W high-brightness lamp bead.

The shape of the fault indicator is shown in fig. 3, the upper half part of the shell part is cylindrical, the lower half part is hemispherical, the upper half part of the cylindrical shell is made of opaque plastics, and the lower half part of the hemispherical shell is made of transparent plastics; the fixing device is made of metal and is fixed on the cable or the overhead line by adopting an elastic clamping structure and a screw fixing structure.

The power supply module directly supplies power for the core control module and the fault indication module, and the core control module supplies power for the current detection module, the voltage detection module and the communication module.

The current detection module consists of a current sensor and an analog-to-digital converter, the current sensor can collect current signals on an overhead line or a cable and output the current signals as analog signals, and the analog-to-digital converter converts the analog signals into digital signals and sends the digital signals to the core control module.

The voltage detection module consists of a voltage sensor and an analog-to-digital converter, the voltage sensor can collect voltage signals on an overhead line or a cable and output the voltage signals as analog signals, and the analog-to-digital converter converts the analog signals into digital signals and sends the digital signals to the core control module.

The communication module has a remote communication function and can transmit the data of the core control module to other terminal equipment of the power system.

The fault indication module is directly connected to the core control module and is controlled by the core control module; the fault indication module is composed of a signal receiving unit and an LED lamp indication unit, wherein the signal receiving unit receives a control signal of the core control module, and the LED lamp indication unit indicates a fault alarm signal.

As shown in fig. 2, the signal processing step of the low voltage distribution network fault indicator includes:

1) signal acquisition: the current detection module and the voltage detection module collect analog signals through the sensor part, and then convert the signals into digital signals through the analog-digital converter and transmit the digital signals to the core control unit;

2) and (3) data judgment: the core control module analyzes the current and voltage signals, judges whether a fault exists or not, and determines the fault type according to whether an interphase short-circuit fault condition is met or a single-phase ground fault condition is met;

3) fault signal communication: if the fault exists, the corresponding interphase short-circuit fault signal or single-phase grounding fault signal is sent to other terminal equipment of the power system through the communication module;

4) and (3) fault indication: the core control module controls the fault indication module to indicate a fault alarm signal.

The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.

Claims (6)

1. A low-voltage distribution network fault indicator is characterized by comprising a shell part, a fixing device and an internal measurement and control unit; the internal measurement and control unit is arranged inside the shell part, and the fixing device is arranged at the bottom of the shell part;

the upper half part of the shell part is made of cylindrical opaque plastic materials, and the lower half part of the shell part is made of hemispherical transparent plastic materials;

the fixing device is made of metal and is fixed on the cable or overhead line by adopting a screw fixing structure and a spring support;

the internal measurement and control unit comprises a power supply module, a current detection module, a voltage detection module, a communication module, a fault indication module and a core control module; the output end of the current detection module and the output end of the voltage detection module are simultaneously connected with the detection data input end of the core control module, the fault indication output end of the core control module is connected with the input end of the fault indication module, and the fault signal output end of the core control module is connected with the input end of the communication module; and the power supply module is simultaneously connected with the core control module and the fault indication module and supplies power.

2. A low voltage distribution network fault indicator according to claim 1, characterized in that: the power supply module directly supplies power to the core control module and the fault indication module, and the core control module supplies power to the current detection module, the voltage detection module, the communication module and the clock module.

3. A low voltage distribution network fault indicator according to claim 1, characterized in that: the current detection module consists of a current sensor and an analog-to-digital converter.

4. A low voltage distribution network fault indicator according to claim 1, characterized in that: the voltage detection module consists of a voltage sensor and an analog-to-digital converter.

5. A low voltage distribution network fault indicator according to claim 1, characterized in that: the communication module has a remote communication function.

6. A low voltage distribution network fault indicator according to claim 1, characterized in that: the fault indication module consists of a signal receiving unit and an LED lamp indication unit.

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