Power distribution area safe electricity use monitoring system and monitoring method

Abstract

The present invention discloses a distribution substation area safety electricity monitoring system and monitoring method, the system includes a field monitoring terminal, a data concentrator and a monitoring main station, the field monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal, the first-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the low-voltage outlet of the distribution transformer in the substation area, the second-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the outlet of the branch switch, and the third-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the lower port of the household meter. The first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are used to collect leakage current data, and the data is uploaded to the data concentrator by LoRa communication mode, and the data concentrator uploads the aggregated data to the monitoring main station by GPRS communication mode. The present invention can accurately locate the leakage section and ensure the safety of electricity use in the substation area.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a power distribution area safety monitoring system and a monitoring method. Background Art

[0002] To ensure the safety of electricity use, distribution substations need to be equipped with leakage protection switches, which are generally divided into three levels: Level 1 leakage protection, that is, the total leakage protection of the distribution transformer, is set on the low-voltage main power supply side of the distribution transformer, and is the total protection of the substation; Level 2 leakage protection, that is, branch line leakage protection, is set on the power supply side of the line branch, mainly to prevent accidents such as leakage grounding on the line branch and the power supply side entering the meter box; Level 3 leakage protection, that is, terminal household leakage protection, is set on the power supply side of the household line entering the meter box, mainly to prevent direct contact electric shock injuries and deaths.

[0003] There are many types of electrical equipment in the distribution area, with complex wiring and frequent leakage hazards. Due to the lack of necessary monitoring means, it is difficult to accurately locate the leakage area and quickly troubleshoot the fault, resulting in frequent tripping and over-tripping of leakage switches, which seriously affects the power consumption of users. In order to eliminate the interference of frequent tripping of leakage switches, it is very common for leakage protection switches to be short-circuited or even not put into use privately, making the three-level leakage protection in the distribution area ineffective and becoming a huge hidden danger to the safe use of electricity in the distribution area. Summary of the invention

[0004] The purpose of the present invention is to provide a power distribution area safety monitoring system and monitoring method to accurately locate the leakage section and ensure the power distribution area safety.

[0005] A distribution substation area safety electricity monitoring system comprises a field monitoring terminal, a data concentrator and a monitoring main station, wherein the field monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal, wherein the first-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the low-voltage outlet of the distribution transformer in the substation area, the second-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the outlet of the branch switch, and the third-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the lower port of the household meter, the first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are all integrated with a LoRa communication module and a leakage collection circuit, the data concentrator is integrated with a GPRS wireless communication module and a LoRa communication module, the first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are used to collect leakage current data, and upload the data to the data concentrator by using a LoRa communication method, and the data concentrator is used to summarize the data, and upload the summarized data to the monitoring main station by using a GPRS communication method.

[0006] According to the distribution station area safety electricity use monitoring system proposed in the present invention, the on-site monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal, forming a three-level monitoring point, which is used for real-time monitoring and analysis of the leakage conditions of the distribution transformer, branch switch and household meter in the substation area. Therefore, when leakage occurs in a certain section, the leakage monitoring terminal of the corresponding section can collect leakage current data and upload the data to the data concentrator via LoRa communication. The data concentrator then uploads the data to the monitoring main station via GPRS communication, so that the operation and maintenance personnel can accurately locate the leakage section, which is helpful to quickly troubleshoot, effectively ensure electricity safety, and improve the operation and maintenance efficiency of the substation area.

[0007] In addition, the power distribution area safety monitoring system provided by the present invention may also have the following additional technical features:

[0008] Furthermore, the monitoring main station includes a gateway, a router, a data server and an application server. The gateway communicates with the data concentrator via GPRS communication, and the router is electrically connected to the gateway, the data server and the application server respectively.

[0009] Furthermore, the first-level leakage monitoring terminal is a Type B leakage monitoring terminal installed in a through-hole manner at the low-voltage outlet of the distribution transformer in the substation, and the second-level leakage monitoring terminal is a Type B leakage monitoring terminal installed in a through-hole manner at the outlet of the branch switch.

[0010] Furthermore, the third-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the lower port of the household meter in a switch-type manner.

[0011] Furthermore, the straight-line distance between the first-level leakage monitoring terminal and the data concentrator, the straight-line distance between the second-level leakage monitoring terminal and the data concentrator, and the straight-line distance between the third-level leakage monitoring terminal and the data concentrator are all no more than 2000 meters.

[0012] Furthermore, the first-level leakage monitoring terminal and the second-level leakage monitoring terminal are powered by a battery self-powered mode and are equipped with a node signal outlet for driving a switch to trip.

[0013] The present invention also provides a monitoring method for the above-mentioned power distribution area safety monitoring system, comprising:

[0014] The first-level leakage monitoring terminal, the second-level leakage monitoring terminal, and the third-level leakage monitoring terminal respectively monitor the leakage conditions at the distribution transformer, the branch switch, and the household meter in the substation area. Each leakage monitoring terminal is set with a steady-state exceeding standard value and a transient exceeding standard value. If the monitoring data does not exceed the standard, the leakage monitoring data is uploaded at intervals of a preset time, and the data is the average value of the monitoring leakage data within the preset time; the steady-state data exceeding standard value is set to 0.9 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 5 consecutive points exceed the standard, it is determined to be a steady-state exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the average value of 5 consecutive exceeding standard data; the transient data exceeding standard value is set to 2 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 3 consecutive points exceed the standard, it is determined to be a transient exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the maximum value of 3 consecutive exceeding standard data;

[0015] The data concentrator corresponds to the data uploading time interval of each leakage monitoring terminal. If there is no transient exceeding standard data in the leakage monitoring terminal under the substation, the data monitored by all the leakage monitoring terminals under it will be uploaded to the monitoring master station at the preset time interval; if there is transient exceeding standard data, the transient exceeding standard data of the corresponding terminal will be uploaded immediately;

[0016] The monitoring master station pushes the transient exceeding standard data and the steady exceeding standard data uploaded by each leakage monitoring terminal, locates the leakage fault, and calculates and pushes the leakage trend alarm signal.

[0017] According to the monitoring method of the distribution station area safety electricity use monitoring system proposed in the present invention, the on-site monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal, forming a three-level monitoring point, which is used for real-time monitoring and analysis of the leakage conditions of the distribution transformer, branch switch and household meter in the substation. Therefore, when leakage occurs in a certain section, the leakage monitoring terminal of the corresponding section can collect leakage current data and upload the data to the data concentrator via LoRa communication, and then the data concentrator uploads the data to the monitoring main station via GPRS communication, so that the operation and maintenance personnel can accurately locate the leakage section, which is helpful for rapid fault detection. In addition, this method is helpful for rapid fault detection and processing of transient faults and early detection and processing of weak points in the insulation of power supply and use in the substation, effectively ensuring the safety of power use in the substation and improving the efficiency of operation and maintenance in the substation.

[0018] In addition, the monitoring method of the power distribution area safety monitoring system provided by the present invention may also have the following additional technical features:

[0019] Furthermore, the monitoring master station uses the following method to locate the leakage fault:

[0020] a1) For transient alarms, directly locate the leakage monitoring terminal where the alarm signal is uploaded;

[0021] a2) For steady-state alarm, if the signal is uploaded by the third-level leakage monitoring terminal, locate the leakage monitoring terminal where the signal is uploaded;

[0022] a3) For steady-state alarm, if the signal is uploaded by the second-level leakage monitoring terminal, it is located at the leakage monitoring terminal where the signal is uploaded.

[0023] Furthermore, the monitoring main station calculates the leakage trend alarm signal using the following method:

[0024] b1) Build a data pool of a single leakage monitoring terminal in units of one month and arrange it in time series;

[0025] b2) With time as the horizontal axis and leakage current value as the vertical axis, the least square method is used to perform a straight line fit on the data to obtain the slope;

[0026] b3) Taking the 95% probability value in the monthly leakage current data pool of a single leakage monitoring terminal as the starting value, calculate the leakage current of the next month according to the slope obtained in step b2). If its maximum value exceeds the set steady-state excess value, the leakage monitoring terminal leakage trend alarm signal is pushed;

[0027] b4) Topology mapping is performed based on distribution station areas. If a leakage trend alarm appears in the third-level leakage monitoring terminal, the monitoring user will be directly identified and located. If a leakage trend alarm appears in the first-level leakage monitoring terminal or the second-level leakage monitoring terminal, and the corresponding lower-level leakage monitoring terminal does not have a trend alarm, the line leakage trend alarm signal will be pushed and the leakage trend alarm line will be identified.

[0028] Further, in step b4), the line leakage trend alarm line positioning method is as follows:

[0029] If the second-level leakage monitoring terminal has a leakage trend alarm and the third-level leakage monitoring terminal has no trend alarm, the line between the second-level leakage monitoring terminal and the third-level leakage monitoring terminal is marked on the topology map; if the first-level leakage monitoring terminal has a leakage trend alarm and both the second-level leakage monitoring terminal and the third-level leakage monitoring terminal have no trend alarm, all lines between the first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are marked on the topology map. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1It is a structural schematic diagram of a power distribution area safety monitoring system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0033] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are for illustrative purposes only and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0035] See also Figure 1 A distribution station area safety electricity monitoring system proposed in one embodiment of the present invention includes a field monitoring terminal, a data concentrator 20 and a monitoring master station. The field monitoring terminal is composed of a first-level leakage monitoring terminal 11, a second-level leakage monitoring terminal 12 and a third-level leakage monitoring terminal 13.

[0036] The first-level leakage monitoring terminal 11 is a type B leakage monitoring terminal installed at the low-voltage outlet of the distribution transformer in the substation. Specifically, the first-level leakage monitoring terminal 11 adopts a type B leakage monitoring terminal installed at the low-voltage outlet of the distribution transformer in the substation. The first-level leakage monitoring terminal 11 integrates a LoRa communication module and a leakage collection circuit to monitor the leakage situation of the section, collect leakage current data, and upload it to the data concentrator 20. In addition, the first-level leakage monitoring terminal 11 is powered by a battery self-powered mode and is equipped with a node signal outlet for driving the switch to trip.

[0037] The second-level leakage monitoring terminal 12 is a type B leakage monitoring terminal installed at the outlet of the branch switch. Specifically, the second-level leakage monitoring terminal 12 is a type B leakage monitoring terminal installed at the outlet of the branch switch in a through-hole manner. The second-level leakage monitoring terminal 12 integrates a LoRa communication module and a leakage collection circuit to monitor the leakage situation of the section, collect leakage current data, and upload it to the data concentrator 20. In addition, the second-level leakage monitoring terminal 12 is powered by a battery self-powered mode and is equipped with a node signal outlet for driving the switch to trip.

[0038] The third-level leakage monitoring terminal 13 is a type B leakage monitoring terminal installed at the lower port of the household meter. Specifically, the third-level leakage monitoring terminal 13 is a type B leakage monitoring terminal installed at the lower port of the household meter in a switch-type manner. The third-level leakage monitoring terminal 13 also integrates a LoRa communication module and a leakage collection circuit, which is used to monitor the leakage situation of the section, collect leakage current data, and upload it to the data concentrator 20. The third-level leakage monitoring terminal 13 specifically integrates a communication function on the basis of a traditional type B leakage switch, which can not only realize the disconnection of leakage protection, but also realize the collection and upload of leakage data.

[0039] Among them, since one distribution transformer in an area is usually responsible for multiple branch switches and household meters, one first-level leakage monitoring terminal 11 can correspond to multiple second-level leakage monitoring terminals 12 and multiple third-level leakage monitoring terminals 13, and one second-level leakage monitoring terminal 12 corresponds to one third-level leakage monitoring terminal 13.

[0040] A three-level monitoring point is formed by the first-level leakage monitoring terminal 11, the second-level leakage monitoring terminal 12 and the third-level leakage monitoring terminal 13, that is, the first-level leakage monitoring terminal 11 is a first-level monitoring point, the second-level leakage monitoring terminal 12 is a second-level monitoring point, and the third-level leakage monitoring terminal 13 is a third-level monitoring point.

[0041] The first-level leakage monitoring terminal 11, the second-level leakage monitoring terminal 12 and the third-level leakage monitoring terminal 13 are all integrated with a LoRa communication module and a leakage collection circuit.

[0042] The data concentrator 20 integrates a GPRS wireless communication module and a LoRa communication module. The first-level leakage monitoring terminal 11, the second-level leakage monitoring terminal 12 and the third-level leakage monitoring terminal 13 are used to collect leakage current data and upload the data to the data concentrator 20 using the LoRa communication method. The data concentrator 20 is used to aggregate the data and upload the aggregated data to the monitoring master station using the GPRS communication method.

[0043] Preferably, the total number of leakage monitoring terminals corresponding to one data concentrator 20 is no more than 100, and the straight-line distance between the first-level leakage monitoring terminal 11 and the data concentrator 20, the straight-line distance between the second-level leakage monitoring terminal 12 and the data concentrator 20, and the straight-line distance between the third-level leakage monitoring terminal 13 and the data concentrator 20 are all no more than 2000 meters.

[0044] The monitoring master station includes a gateway 31, a router 32, a data server 33 and an application server 34. The gateway 31 communicates with the data concentrator 203 via GPRS communication, and the router 2 is electrically connected to the gateway 31, the data server 33 and the application server 34. The data server 33 and the application server 34 can communicate wirelessly with a smart phone, and a corresponding application program (APP) can be installed on the smart phone to provide a window for interaction with the user. Specifically, data query and display can be realized through mobile phone APP and WEB.

[0045] According to the monitoring system proposed in this embodiment, the on-site monitoring terminal is composed of a first-level leakage monitoring terminal 11, a second-level leakage monitoring terminal 12 and a third-level leakage monitoring terminal 13, forming a three-level monitoring point, which is used for real-time monitoring and analysis of the leakage conditions of the distribution transformer, branch switch and household meter in the substation. Therefore, when leakage occurs in a certain section, the leakage monitoring terminal of the corresponding section can collect leakage current data and upload the data to the data concentrator 20 via LoRa communication. The data concentrator 20 then uses GPRS communication to upload the data to the monitoring main station, so that the operation and maintenance personnel can accurately locate the leakage section, which is helpful for rapid fault detection. In addition, this method is helpful for rapid fault detection and processing of transient faults and early detection and processing of weak points in the insulation of power supply and use in the substation, effectively ensuring the safety of power use in the substation and improving the efficiency of operation and maintenance in the substation.

[0046] The embodiment of the present invention further provides a monitoring method of the above-mentioned power distribution area safety monitoring system, comprising:

[0047] The first-level leakage monitoring terminal 11, the second-level leakage monitoring terminal 12, and the third-level leakage monitoring terminal 13 respectively monitor the leakage conditions at the distribution transformer, the branch switch, and the household meter in the substation area. Each leakage monitoring terminal is set with a steady-state exceeding standard value and a transient exceeding standard value. If the monitoring data does not exceed the standard, the leakage monitoring data is uploaded at intervals of a preset time (for example, 5 minutes, 10 minutes, etc.), and the data is the average value of the monitoring leakage data within the preset time; the steady-state data exceeding standard value is set to 0.9 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 5 consecutive points exceed the standard, it is determined to be a steady-state exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the average value of 5 consecutive exceeding standard data; the transient data exceeding standard value is set to 2 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 3 consecutive points exceed the standard, it is determined to be a transient exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the maximum value of 3 consecutive exceeding standard data;

[0048] The data concentrator 20 corresponds to the data uploading time interval of each leakage monitoring terminal. If there is no transient exceeding standard data in the leakage monitoring terminal under the substation, the data monitored by all the leakage monitoring terminals under it will be uploaded to the monitoring master station at the preset time interval; if there is transient exceeding standard data, the transient exceeding standard data of the corresponding terminal will be uploaded immediately;

[0049] In specific implementation, when 20% of the leakage monitoring terminals under the substation exceed the leakage data standard for one hour in a row, the data concentrator 20 can upload an alarm signal of the leakage abnormal substation; if 20% of the leakage monitoring terminals under the substation fail to collect leakage data for one hour in a row, the data concentrator 20 can upload an alarm signal of the communication abnormal substation.

[0050] The monitoring master station pushes the transient exceeding standard data and the steady exceeding standard data uploaded by each leakage monitoring terminal, locates the leakage fault, and calculates and pushes the leakage trend alarm signal.

[0051] The monitoring master station specifically uses the following method to locate the leakage fault:

[0052] a1) For transient alarms, directly locate the leakage monitoring terminal where the alarm signal is uploaded;

[0053] a2) For steady-state alarm, if the signal is uploaded by the third-level leakage monitoring terminal 13, locate the leakage monitoring terminal where the signal is uploaded;

[0054] a3) For a steady-state alarm, if it is a signal uploaded by the second-level leakage monitoring terminal 12, it is located at the leakage monitoring terminal where the signal is uploaded.

[0055] The monitoring master station uses the following method to calculate the leakage trend alarm signal:

[0056] b1) Build a data pool of a single leakage monitoring terminal in units of one month and arrange it in time series;

[0057] b2) With time as the horizontal axis and leakage current value as the vertical axis, the least square method is used to perform a straight line fit on the data to obtain the slope;

[0058] b3) Taking the 95% probability value in the monthly leakage current data pool of a single leakage monitoring terminal as the starting value, calculate the leakage current of the next month according to the slope obtained in step b2). If its maximum value exceeds the set steady-state excess value, the leakage monitoring terminal leakage trend alarm signal is pushed;

[0059] b4) Topology correspondence is performed based on the distribution station area. If a leakage trend alarm occurs at the third-level leakage monitoring terminal 13, the monitoring user is directly identified and located; if a leakage trend alarm occurs at the first-level leakage monitoring terminal 11 or the second-level leakage monitoring terminal 12, and the corresponding lower-level leakage monitoring terminal does not have a trend alarm, the line leakage trend alarm signal is pushed, and the leakage trend alarm line is identified at the same time.

[0060] Among them, in step b4), the line leakage trend alarm line positioning method is as follows:

[0061] If the second-level leakage monitoring terminal 12 has a leakage trend alarm, and the third-level leakage monitoring terminal 13 has no trend alarm, the line between the second-level leakage monitoring terminal 12 and the third-level leakage monitoring terminal 13 is marked on the topology map; if the first-level leakage monitoring terminal 11 has a leakage trend alarm, and neither the second-level leakage monitoring terminal 12 nor the third-level leakage monitoring terminal 13 has a trend alarm, all lines between the first-level leakage monitoring terminal 11, the second-level leakage monitoring terminal 12, and the third-level leakage monitoring terminal 13 are marked on the topology map.

[0062] According to the monitoring system method proposed in this embodiment, the on-site monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal, forming a three-level monitoring point, which is used for real-time monitoring and analysis of the leakage conditions of the distribution transformer, branch switch and household meter in the substation. Therefore, when leakage occurs in a certain section, the leakage monitoring terminal of the corresponding section can collect leakage current data and upload the data to the data concentrator via LoRa communication. The data concentrator then uploads the data to the monitoring main station via GPRS communication, so that the operation and maintenance personnel can accurately locate the leakage section, which is helpful for rapid troubleshooting. In addition, this method is helpful for rapid troubleshooting and handling of transient faults and early discovery and handling of weak points in the insulation of power supply and use in the substation, effectively ensuring the safety of power use in the substation and improving the efficiency of operation and maintenance in the substation.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0064] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A monitoring method for a power distribution area safety monitoring system, characterized in that: The power distribution area safety monitoring system includes a field monitoring terminal, a data concentrator and a monitoring main station. The field monitoring terminal is composed of a first-level leakage monitoring terminal, a second-level leakage monitoring terminal and a third-level leakage monitoring terminal. The first-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the low-voltage outlet of the distribution transformer in the area, the second-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the outlet of the branch switch, and the third-level leakage monitoring terminal is a B-type leakage monitoring terminal installed at the lower port of the household meter. The first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are all integrated with a LoRa communication module and a leakage collection circuit. The data concentrator integrates a GPRS wireless communication module and a LoRa communication module. The first-level leakage monitoring terminal, the second-level leakage monitoring terminal and the third-level leakage monitoring terminal are used to collect leakage current data, and upload the data to the data concentrator using the LoRa communication method. The data concentrator is used to summarize the data and upload the summarized data to the monitoring main station using the GPRS communication method. Monitoring methods include: The first-level leakage monitoring terminal, the second-level leakage monitoring terminal, and the third-level leakage monitoring terminal respectively monitor the leakage conditions at the distribution transformer, the branch switch, and the household meter in the substation area. Each leakage monitoring terminal is set with a steady-state exceeding standard value and a transient exceeding standard value. If the monitoring data does not exceed the standard, the leakage monitoring data is uploaded at intervals of a preset time, and the data is the average value of the monitoring leakage data within the preset time; the steady-state data exceeding standard value is set to 0.9 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 5 consecutive points exceed the standard, it is determined to be a steady-state exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the average value of 5 consecutive exceeding standard data; the transient data exceeding standard value is set to 2 times the leakage limit value required by the leakage monitoring terminal standard. If the monitoring data of 3 consecutive points exceed the standard, it is determined to be a transient exceeding standard. The exceeding standard data is uploaded in real time in an alarm mode, and the data is the maximum value of 3 consecutive exceeding standard data; The data concentrator corresponds to the data uploading time interval of each leakage monitoring terminal. If there is no transient exceeding standard data in the leakage monitoring terminal under the substation, the data monitored by all the leakage monitoring terminals under it will be uploaded to the monitoring main station at the preset time interval; if there is transient exceeding standard data, the transient exceeding standard data of the corresponding leakage monitoring terminal will be uploaded immediately; The monitoring master station pushes the transient exceeding standard data and the steady exceeding standard data uploaded by each leakage monitoring terminal, locates the leakage fault, and calculates and pushes the leakage trend alarm signal.

2. The monitoring method of the power distribution area safety monitoring system according to claim 1 is characterized in that: The monitoring main station includes a gateway, a router, a data server and an application server. The gateway communicates with the data concentrator via GPRS communication. The router is electrically connected to the gateway, the data server and the application server respectively.

3. The monitoring method of the power distribution area safety monitoring system according to claim 1 is characterized in that: The first-level leakage monitoring terminal is a Type B leakage monitoring terminal installed in a through-hole manner at the low-voltage outlet end of the distribution transformer in the substation area, and the second-level leakage monitoring terminal is a Type B leakage monitoring terminal installed in a through-hole manner at the outlet of the branch switch.

4. The monitoring method of the power distribution area safety monitoring system according to claim 1 is characterized in that: The third-level leakage monitoring terminal is a B-type leakage monitoring terminal which is installed in a switch-type manner at the lower port of the household meter.

5. The monitoring method of the power distribution area safety monitoring system according to claim 1 is characterized in that: The straight-line distance between the first-level leakage monitoring terminal and the data concentrator, the straight-line distance between the second-level leakage monitoring terminal and the data concentrator, and the straight-line distance between the third-level leakage monitoring terminal and the data concentrator are all no more than 2000 meters.

6. The monitoring method of the power distribution area safety monitoring system according to claim 1, characterized in that: The first-level leakage monitoring terminal and the second-level leakage monitoring terminal are powered by a battery self-powered mode and are equipped with a node signal outlet for driving the switch to trip.

7. The monitoring method of the power distribution area safety monitoring system according to claim 1, characterized in that: The monitoring master station uses the following method to locate leakage faults: a1) For transient alarms, directly locate the leakage monitoring terminal where the alarm signal is uploaded; a2) For steady-state alarm, if the signal is uploaded by the third-level leakage monitoring terminal, locate the leakage monitoring terminal where the signal is uploaded; a3) For steady-state alarm, if the signal is uploaded by the second-level leakage monitoring terminal, it is located at the leakage monitoring terminal where the signal is uploaded.

8. The monitoring method of the power distribution area safety monitoring system according to claim 1, characterized in that: The monitoring master station uses the following method to calculate the leakage trend alarm signal: b1) Build a data pool of a single leakage monitoring terminal in units of one month and arrange it in time series; b2) With time as the horizontal axis and leakage current value as the vertical axis, the least square method is used to perform a straight line fit on the data to obtain the slope; b3) Taking the 95% probability value in the monthly leakage current data pool of a single leakage monitoring terminal as the starting value, calculate the leakage current of the next month according to the slope obtained in step b2). If its maximum value exceeds the set steady-state excess value, the leakage monitoring terminal leakage trend alarm signal is pushed; b4) Topology mapping is performed based on distribution station areas. If a leakage trend alarm appears in the third-level leakage monitoring terminal, the monitoring user will be directly identified and located. If a leakage trend alarm appears in the first-level leakage monitoring terminal or the second-level leakage monitoring terminal, and the corresponding lower-level leakage monitoring terminal does not have a trend alarm, the line leakage trend alarm signal will be pushed and the leakage trend alarm line will be identified.

9. The monitoring method of the power distribution area safety monitoring system according to claim 8, characterized in that: In step b4), the method for locating the line leakage trend alarm line is as follows: if the second-level leakage monitoring terminal has a leakage trend alarm, and the third-level leakage monitoring terminal has no trend alarm, then the line between the second-level leakage monitoring terminal and the third-level leakage monitoring terminal is marked on the topology map; If the first-level leakage monitoring terminal has a leakage trend alarm, and the second-level leakage monitoring terminal and the third-level leakage monitoring terminal have no trend alarm, all lines between the first-level leakage monitoring terminal, the second-level leakage monitoring terminal, and the third-level leakage monitoring terminal are marked on the topology diagram.

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