CN114062756A - Residual current monitoring device and system of feeder circuit - Google Patents
Residual current monitoring device and system of feeder circuit Download PDFInfo
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- CN114062756A CN114062756A CN202111214870.5A CN202111214870A CN114062756A CN 114062756 A CN114062756 A CN 114062756A CN 202111214870 A CN202111214870 A CN 202111214870A CN 114062756 A CN114062756 A CN 114062756A
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- 238000009413 insulation Methods 0.000 abstract description 12
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- 238000013024 troubleshooting Methods 0.000 description 5
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention relates to a residual current monitoring device and a residual current monitoring system of a feeder line loop, which realize the monitoring of the real-time residual current of each alternating current loop in a station by configuring equipment such as the residual current monitoring device and the like in an alternating current system for the station, thereby judging whether the system has an insulation fault or not and helping operation and maintenance personnel to quickly position the fault loop. According to the invention, through the residual current monitoring device, the alternating current monitoring device and the three-level monitoring framework of the background, the residual current of each alternating current feeder circuit in the low-voltage alternating current power supply system for the real-time monitoring station is realized, the operation and maintenance personnel can be helped to quickly locate the fault circuit, the search time of the alternating current insulation fault is greatly shortened, and the reliability of the low-voltage alternating current power supply system in the station is ensured. The alternating current feeder circuit in the existing station alternating current power supply system can be modified, the real-time monitoring of the residual current of each feeder circuit can be realized without complex wiring, the main wiring of the system is not increased, and the realization is more convenient.
Description
Technical Field
The invention relates to the technical field of power systems, in particular to a residual current monitoring device and system of a feeder line loop.
Background
The alternating current system for the transformer substation is used for supplying power to primary and secondary equipment of the transformer substation, is an indispensable link for ensuring reliable power supply of the transformer substation, and can directly influence the normal use of running equipment when abnormal conditions occur. Wherein station is with alternating current system insulation fault will bring great potential safety hazard for the station interior alternating current power supply, insulation fault can reflect out through the residual current, the size of residual current means the severity of electric leakage, it is past that there is the current in the circuit, the circuit can generate heat, when the residual current is too big in the circuit, the temperature of circuit can rise constantly, even burn out the circuit, arouse electric fire accident, seriously threaten the safety of transformer substation, consequently monitor with alternating current system residual current station very importantly.
In the prior art, the conventional operation mode of the station alternating current system is to perform troubleshooting until a short-circuit fault occurs, the troubleshooting mode is to perform one-by-one troubleshooting on each loop generally through a handheld residual current monitoring device, the troubleshooting mode is not beneficial to the stability of alternating current power supply in a station at first, then the troubleshooting efficiency is low, finally, the method can only find uninterrupted leakage current, and the intermittent leakage current is easy to neglect. And the simultaneity is difficult to guarantee for the monitoring of the transformer end and the user end, which brings uncertain factors for the analysis of leakage current and the positioning of leakage current source. If the insulation fault of the alternating current system in the station can be monitored in real time, the short-circuit fault is eliminated when the short-circuit fault is not developed, and the operation reliability of the short-circuit fault is greatly improved.
Disclosure of Invention
Based on the above situation in the prior art, an object of the present invention is to provide a device and a system for monitoring residual current in a feeder line loop, in which, by configuring devices such as a residual current monitoring device in an ac system for a station, real-time residual current in each ac loop in the station is monitored, so as to determine whether an insulation fault exists in the system, help an operation and maintenance worker to quickly locate a faulty loop, greatly shorten the time for finding an ac insulation fault, and ensure the reliability of an ac power supply system in the station.
In order to achieve the above object, according to one aspect of the present invention, there is provided a residual current monitoring device for a feeder circuit, including a monitoring host, a current collecting module, and a plurality of current transformers; wherein the content of the first and second substances,
one or more current transformers are configured on the feeder circuit, and the current transformers are used for measuring the passing feeder current;
the current acquisition module acquires currents measured by current transformers on the feeder line loop and uploads the currents to the monitoring host through the communication bus;
the monitoring host is connected with the current acquisition module through a communication bus so as to receive the current acquired by the current acquisition module and calculate the residual current of the feeder line loop according to the current and the configuration mode of the mutual inductor.
Furthermore, one or more current transformers are configured on the feeder line loop, wherein each phase line and each zero line of the feeder line loop respectively penetrate through one current transformer; alternatively, the first and second electrodes may be,
all phase lines of the feeder line loop pass through a current transformer, and a zero line passes through the current transformer; or
All phase lines and zero lines of the feeder line loop pass through a current transformer together.
Further, the residual current is calculated by:
each phase line and the zero line of the feeder line loop respectively penetrate through a current transformer, or all the phase lines of the feeder line loop penetrate through a current transformer, and when the zero line penetrates through a current transformer, the residual current is the root mean square value of the synthesized data phases of all the current transformers
Further, the residual current is calculated by,
when all phase lines and zero lines of the feeder line loop pass through one current transformer together, the residual current is the root mean square value of data acquired by the current transformer.
Further, the monitoring host is connected with one or more current collection modules.
Furthermore, each current acquisition module is directly connected with the monitoring host through a communication bus; or indirectly connected with the monitoring host through the cascade interfaces of other current acquisition modules.
Further, the communication between the monitoring host and the current collection module is determined by the unique address code of the current collection module.
Furthermore, the monitoring host machine also has an alarm function, and when the calculated residual current of the feeder line exceeds a preset early warning threshold value, an acousto-optic alarm signal is sent out.
According to a second aspect of the present invention, there is provided a residual current monitoring system for a feeder circuit, comprising a background monitoring device, an ac monitoring device, a residual current monitoring device, an ac power supply and an ac power supply switching device; wherein the content of the first and second substances,
the background monitoring device, the alternating current monitoring device and the residual current monitoring device are sequentially connected through a communication bus;
the residual current monitoring device is connected with a plurality of feeder loops to monitor the residual current of each feeder loop, and comprises the residual current monitoring device as claimed in any one of claims 1 to 8;
the alternating current power supply comprises a plurality of alternating current power supplies which are respectively connected to the plurality of feeder circuits through the alternating current power supply switching device;
the alternating current power supply switching device is used for switching an alternating current power supply connected to the feeder line loop.
Further, the communication bus comprises an RS485 communication bus.
In summary, the present invention provides a device and a system for monitoring residual current of a feeder line loop, which implement monitoring of real-time residual current of each ac loop in a station by configuring devices such as a residual current monitoring device in an ac system for a station, so as to determine whether an insulation fault exists in the system, and help an operation and maintenance worker to quickly locate a faulty loop. According to the invention, through the residual current monitoring device, the alternating current monitoring device and the three-level monitoring framework of the background, the residual current of each alternating current feeder circuit in the low-voltage alternating current power supply system for the real-time monitoring station is realized, the operation and maintenance personnel can be helped to quickly locate the fault circuit, the search time of the alternating current insulation fault is greatly shortened, and the reliability of the low-voltage alternating current power supply system in the station is ensured. The alternating current feeder circuit in the existing station alternating current power supply system can be modified, real-time monitoring of residual current of each feeder circuit can be achieved without complex wiring, main wiring of the system is not increased, the system is convenient to achieve, and the system can be directly applied to a new station alternating current power supply system to be operated.
Drawings
Fig. 1 is a schematic structural diagram of a residual current monitoring device of a feeder circuit of the present invention;
fig. 2 is a schematic structural diagram of a residual current monitoring system of a feeder circuit of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings. According to an embodiment of the invention, a residual current monitoring device of a feeder circuit is provided, and a schematic structural diagram of the monitoring device is shown in fig. 1, and the monitoring device comprises a monitoring host, a current acquisition module and a plurality of current transformers.
One or more current transformers are configured on the feeder line loop, the current transformers are alternating current transformers, and the alternating current transformers are used for measuring the passing feeder line current. Wherein, configuring one or more current transformers on the feeder circuit may include the following: each phase line and the zero line of the feeder line loop respectively penetrate through a current transformer; or all phase lines of the feeder line loop pass through a current transformer, and a zero line passes through a current transformer; or all phase lines and zero lines of the feeder line loop pass through one current transformer together. Each feeder line loop can be provided with a plurality of alternating current transformers, a three-phase loop can be provided with 4 alternating current transformers at most, a single-phase loop can be provided with 2 alternating current transformers at most, each phase line is connected with one transformer in series, and N lines are also connected with one transformer in series independently. If 2 alternating current transformers are configured when the A/B/C three-phase lines (single-phase L lines) and the N lines are not connected together, the A/B/C three-phase lines (single-phase L lines) penetrate through the current transformers 1, and the N lines penetrate through the current transformers 2; if the A/B/C three-phase lines (single-phase L lines) and the N lines are connected together, the four lines (single-phase two lines) can simultaneously pass through 1 AC current transformer.
The current acquisition module acquires currents measured by the current transformers on the feeder line loop and uploads the currents to the monitoring host through the communication bus. Every current acquisition module can articulate a plurality of current transformer, in this embodiment, for example can articulate 12 current transformer, and after current transformer passes through special interface access current acquisition module, current acquisition module can automatic identification current transformer, need not artifical the setting.
The monitoring host is connected with the current acquisition module through a communication bus, and the communication bus CAN be a CAN bus, for example, so as to receive the current acquired by the current acquisition module and calculate the residual current of the feeder line loop according to the current and the configuration mode of the mutual inductor. Aiming at the condition that the current acquisition modules are connected with the current transformer in a hanging mode, the residual current can be calculated in the following mode: each phase line and the zero line of the feeder line loop respectively penetrate through a current transformer, or all the phase lines of the feeder line loop penetrate through a current transformer, and when the zero line penetrates through a current transformer, the residual current is the root mean square value of the synthesized data phases of all the current transformers. When all phase lines and zero lines of the feeder line loop pass through one current transformer together, the residual current is the root mean square value of data acquired by the current transformer. That is to say, the actual residual current of the feeder line loop is the root mean square value of the waveform collected by the residual current transformer; and under the condition that a plurality of transformers exist in the feeder line loop, the residual current is the root mean square value after the data phases of all the residual current transformers are synthesized.
The reason for the residual current is that the normal three-phase ac feeder circuit A, B, C satisfies the following equation 1 for the three-phase current and the N-line current:
the normal single-phase alternating current feeder circuit L-line current and N-line current satisfy the following formula 2:
when the three-phase feeder line loop is grounded, the equation 1 does not hold, namely the vector sum of the three-phase current and the N-phase current is not 0; when the single-phase feeder circuit is grounded, the above equation 2 does not hold, that is, the vector sum of the L-line current and the N-line current is not 0; the vector sum current is the earth residual current of the alternating current loop, and in the embodiment of the invention, the earth residual current obtained by detection is used as the basis for judging whether the feeder line loop has an insulation fault or not by utilizing the principle.
The monitoring host can be connected with one or more current collection modules. Each current acquisition module is directly connected with the monitoring host through a communication bus; or indirectly connected with the monitoring host through the cascade interfaces of other current acquisition modules. The communication between the monitoring host and the current acquisition module is determined by the unique address code of the current acquisition module. Two connection modes are supported between the monitoring host and the current acquisition module: star-shaped links and chain links. Each current acquisition module can be directly connected with the monitoring host through a communication bus, and can also be indirectly connected with the monitoring host through a cascade port of another current acquisition module, so that the installation and wiring are convenient. The communication between the monitoring host and the current acquisition module is determined by the unique address code of the current acquisition module and is irrelevant to the physical position of the current acquisition module, so that high flexibility is brought to the configuration of a field system. The monitoring host and the current acquisition module can be hot-plugged in an electrified mode, and the monitoring host can automatically identify the current acquisition module without manual setting.
Furthermore, the monitoring host machine also has an alarm function, and when the residual current calculated by the monitoring host machine exceeds a preset early warning threshold value, an acousto-optic alarm signal is sent out.
According to a second embodiment of the present invention, a system for monitoring a residual current of a feeder circuit is provided, where a schematic structural diagram of the system is shown in fig. 2, and the system includes a background monitoring device, an ac monitoring device, a residual current monitoring device, an ac power supply, and an ac power supply switching device. The host of the residual current monitoring device can be fixed on a screen body of the system, is a core control unit of the whole monitoring system, and is also a main interface for information display and information input setting. The current transformers are arranged at the outgoing line loops of the alternating current feeder lines.
The background monitoring device, the alternating current monitoring device and the residual current monitoring device are sequentially connected through a communication bus, and the communication bus can be an RS485 bus, for example.
The residual current monitoring device is connected with a plurality of feeder loops to monitor the residual current of each feeder loop, and comprises the residual current monitoring device according to the first embodiment of the invention;
the alternating current power supply can be a plurality of alternating current power supplies which are respectively connected to the plurality of feeder circuits through the alternating current power supply switching device; the alternating current power supply switching device is used for switching an alternating current power supply connected to the feeder line loop.
The monitoring host of the residual current monitoring device receives current information of each alternating current transformer uploaded by the current acquisition module in real time, residual current of each loop is calculated through loop configuration information, and then the residual current is displayed through liquid crystal on the host. And then the monitoring host uploads the residual current values and the alarm information of each loop to the alternating current monitoring device through communication, and the alternating current monitoring device transmits the residual current values and the alarm information of each loop to the background through communication.
The alarm records of the residual current of each loop are automatically stored in the EEPROM of the monitoring host for reference. The record comprises the date and time of the occurrence of the fault, the configuration of the mutual inductor, the residual current value of each mutual inductor, the fault waveform, the residual current of the circuit and the synthesized waveform data, and the maximum storage capacity of the grounding record number is determined according to the size of the memory.
In summary, the present invention provides a device and a system for monitoring residual current of a feeder line loop, which implement monitoring of real-time residual current of each ac loop in a station through devices such as a residual current monitoring device in an ac system for a station, so as to determine whether the system has an insulation fault, and help an operation and maintenance person to quickly locate a faulty loop. According to the invention, through the residual current monitoring device, the alternating current monitoring device and the three-level monitoring framework of the background, the residual current of each alternating current feeder circuit in the low-voltage alternating current power supply system for the real-time monitoring station is realized, the operation and maintenance personnel can be helped to quickly locate the fault circuit, the search time of the alternating current insulation fault is greatly shortened, and the reliability of the low-voltage alternating current power supply system in the station is ensured. The alternating current feeder circuit in the existing station alternating current power supply system can be modified, real-time monitoring of residual current of each feeder circuit can be achieved without complex wiring, main wiring of the system is not increased, the system is convenient to achieve, and the system can also be directly applied to a new station alternating current power supply system to be operated.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.
Claims (10)
1. A residual current monitoring device of a feeder line loop is characterized by comprising a monitoring host, a current acquisition module and a plurality of current transformers; wherein the content of the first and second substances,
one or more current transformers are configured on the feeder circuit, and the current transformers are used for measuring the passing feeder current; the current acquisition module acquires currents measured by current transformers on the feeder line loop and uploads the currents to the monitoring host through the communication bus;
the monitoring host is connected with the current acquisition module through a communication bus so as to receive the current acquired by the current acquisition module and calculate the residual current of the feeder line loop according to the current and the configuration mode of the mutual inductor.
2. The apparatus of claim 1 wherein the feeder circuit having one or more current transformers disposed thereon comprises one current transformer passing over each of the phase and neutral lines of the feeder circuit; or all phase lines of the feeder line loop pass through a current transformer, and a zero line passes through a current transformer; or all phase lines and zero lines of the feeder line loop pass through one current transformer together.
3. The apparatus of claim 2, wherein the residual current is calculated by: each phase line and the zero line of the feeder line loop respectively penetrate through a current transformer, or all the phase lines of the feeder line loop penetrate through a current transformer, and when the zero line penetrates through a current transformer, the residual current is the root mean square value of the synthesized data phases of all the current transformers.
4. The apparatus of claim 2, wherein the residual current is calculated by: when all phase lines and zero lines of the feeder line loop pass through one current transformer together, the residual current is the root mean square value of data acquired by the current transformer.
5. The device of claim 1, wherein the monitoring host is connected to one or more current collection modules.
6. The device of claim 5, wherein each current collection module is directly associated with the monitoring host through a communication bus; or indirectly connected with the monitoring host through the cascade interfaces of other current acquisition modules.
7. The apparatus of claim 6, wherein the communication between the monitoring host and the current collection module is determined by a unique address code of the current collection module.
8. The device according to claim 1, wherein the monitoring host further has an alarm function, and when the residual current calculated by the monitoring host exceeds a preset early warning threshold value, an audible and visual alarm signal is given.
9. A residual current monitoring system of a feeder line loop is characterized by comprising a background monitoring device, an alternating current monitoring device, a residual current monitoring device, an alternating current power supply and an alternating current power supply switching device; the background monitoring device, the alternating current monitoring device and the residual current monitoring device are sequentially connected through a communication bus; the residual current monitoring device is connected with a plurality of feeder loops to monitor the residual current of each feeder loop, and comprises the residual current monitoring device as claimed in any one of claims 1 to 8;
the alternating current power supply comprises a plurality of alternating current power supplies which are respectively connected to the plurality of feeder circuits through the alternating current power supply switching device; the alternating current power supply switching device is used for switching an alternating current power supply connected to the feeder line loop.
10. The system of claim 9, wherein the communication bus comprises an RS485 communication bus.
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| CN202111214870.5A CN114062756A (en) | 2021-10-19 | 2021-10-19 | Residual current monitoring device and system of feeder circuit |
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- 2021-10-19 CN CN202111214870.5A patent/CN114062756A/en active Pending
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