CN112834885B - Power supply line insulation state assessment based on power supply line leakage current and humidity relation identification - Google Patents
Power supply line insulation state assessment based on power supply line leakage current and humidity relation identificationDownload PDFInfo
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- CN112834885B CN112834885BCN202110020333.0ACN202110020333ACN112834885BCN 112834885 BCN112834885 BCN 112834885BCN 202110020333 ACN202110020333 ACN 202110020333ACN 112834885 BCN112834885 BCN 112834885B
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- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
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- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
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Abstract
Description
Translated fromChinese技术领域technical field
本发明属于供电系统电气设备漏电监测领域，提供了基于供电线路漏电流与湿度关系辨识的供电线路绝缘状态评估。The invention belongs to the field of leakage monitoring of electrical equipment in a power supply system, and provides power supply line insulation state evaluation based on identification of the relationship between the leakage current and humidity of the power supply line.
背景技术Background technique
目前农村电网多采用三级漏电保护模式，分别安装在公用变压器、电表箱和客户端，或跳过电表箱的二级漏电保护模式。目前农村家庭电线布置多隐藏在墙内，由于线路质量和施工工艺等因素的影响，线路容易产生漏电流。此外，农村电网输电方式多采用三相四线制，10kV输电线路多采用16mm2或25mm2线径，并部分存在裸线问题。尤其是山区农村电网易受到泥石流，树木折断倾轧等自然灾害影响，输电线路时常发生漏电、短路等故障情况。At present, the rural power grid mostly adopts three-level leakage protection mode, which is installed in the public transformer, meter box and client, or skips the second-level leakage protection mode of the meter box. At present, the wiring layout of rural households is mostly hidden in the wall. Due to the influence of factors such as line quality and construction technology, the line is prone to leakage current. In addition, the three-phase four-wire system is mostly used in rural power grids, and the 10kV transmission lines mostly use16mm2 or25mm2 wire diameters, and there are some problems with bare wires. In particular, rural power grids in mountainous areas are easily affected by natural disasters such as mudslides, broken trees and rolling, and transmission lines often experience leakage, short-circuit and other faults.
由于农村电网地域宽广，用电客户分散，且多为单相用电。因此，发生故障时，受影响的家庭用户数量通常较少，这就导致故障发生后经常未能及时上报，进而导致故障线路不能得到及时处理，使周边居民及动物存在触电的风险。Due to the wide area of rural power grids, electricity customers are scattered, and most of them use single-phase electricity. Therefore, when a fault occurs, the number of affected household users is usually small, which often leads to failure to report the fault in time after the occurrence of the fault, which in turn causes the faulty line to be unable to be dealt with in a timely manner, putting the surrounding residents and animals at risk of electric shock.
综上所述，如何及时发现农村地区电网供电线路的绝缘故障成为了本领域技术人员急需解决的问题。To sum up, how to timely detect the insulation fault of the power supply line of the power grid in rural areas has become an urgent problem to be solved by those skilled in the art.
发明内容SUMMARY OF THE INVENTION
因此，本发明需要解决的问题是如何及时发现农村地区电网供电线路的绝缘故障，避免发生触电事故。Therefore, the problem to be solved by the present invention is how to find out the insulation fault of the power supply line of the power grid in rural areas in time to avoid electric shock accidents.
为了解决上述技术问题，本发明采用了如下的技术方案：In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:
基于供电线路漏电流与湿度关系辨识的供电线路绝缘状态评估，包括：Power supply line insulation condition assessment based on the relationship between power supply line leakage current and humidity identification, including:
S1、利用湿度传感器及漏电流传感器获取目标线路的环境湿度值及漏电流值；S1. Use the humidity sensor and the leakage current sensor to obtain the ambient humidity value and leakage current value of the target line;
S2、将目标电路的环境湿度值输入漏电流与湿度之间的关联模型，得到漏电流模型预测值；S2. Input the ambient humidity value of the target circuit into the correlation model between leakage current and humidity, and obtain the predicted value of the leakage current model;
S3、计算漏电流模型预测值与漏电流值的差值，若差值大于预设阈值则判断目标线路绝缘异常，若差值小于或等于预设阈值则判断目标线路绝缘正常。S3. Calculate the difference between the predicted value of the leakage current model and the leakage current value. If the difference is greater than a preset threshold, determine that the insulation of the target line is abnormal, and if the difference is less than or equal to the preset threshold, determine that the insulation of the target line is normal.
优选地，所述漏电流与湿度之间的关联模型的建立方法包括：Preferably, the method for establishing the correlation model between the leakage current and humidity includes:
采集历史环境湿度值集合与历史漏电流值集合，利用均方最小二乘拟合目标的方法，得到漏电流与湿度之间的拟合方程，建立漏电流与湿度之间的关联模型。Collect the set of historical environmental humidity values and the set of historical leakage current values, and use the mean square least squares method to fit the target to obtain a fitting equation between leakage current and humidity, and establish a correlation model between leakage current and humidity.
优选地，设漏电流值为yl、环境湿度值为xi，记yl＝f(xi)；Preferably, let the leakage current value be yl and the ambient humidity value bexi , and denote yl =f(xi );
f(xi)＝a1r1(x1)+a2r2(x2)+…+amrm(xm) (1)f(xi )=a1 r1 (x1 )+a2 r2 (x2 )+…+am rm (xm ) (1)
r1(x1)至rm(xm)是一组线性无关的函数，aj是待定系数，j＝1,2,3,…,m，m＜n，n是在目标线路的不同地点的测量次数，m是线性无关组中元素个数；r1 (x1 ) to rm (xm ) are a set of linearly independent functions, aj are undetermined coefficients, j=1,2,3,...,m , m<n, n is the difference in the target line The number of measurements of the location, m is the number of elements in the linearly independent group;
记remember
为选取a1,a2,…,am，使J(a1,a2,…,am)最小，利用极值的必要条件
即which is
记remember
R表示参数矩阵，Α表示待定系数矩阵，Y表示漏电流矩阵，此时，方程组(5)可表示为R represents the parameter matrix, A represents the undetermined coefficient matrix, and Y represents the leakage current matrix. At this time, the equation group (5) can be expressed as
RTRA＝RTY (6)RT RA = RT Y (6)
当选取的函数{r1(x),r2(x),…,rm(x)}线性无关时，R列满秩，RTR可逆，于是方程组(6)有唯一解：When the selected function {r1 (x),r2 (x),…,rm (x)} is linearly independent, the R column is full rank, and RT R is invertible, so the equation system (6) has a unique solution:
A＝(RTR)-1RTY (7)A=(RT R)-1 RT Y (7)
得到漏电流与湿度之间的拟合方程。A fitting equation between leakage current and humidity is obtained.
与现有技术相比，本发明具有以下优点：Compared with the prior art, the present invention has the following advantages:
为解决现有的电力系统供电线路绝缘状态评估的不灵敏和不可靠，本发明首先利用湿度传感器、漏电传感器获取供电设备的环境湿度数据和漏电流数据，通过积累某时间周期的环境湿度和漏电流数据，然后拟合得到环境湿度与漏电流之间的关系曲线，作为该供电线路漏电流与环境湿度之间的关联特性。将新采集得到的湿度与漏电流值，代入历史已得到的拟合方程进行校核，当满足历史拟合特性时，说明线路绝缘状态完好；当不满足历史拟合特性时，判断供电设备绝缘异常，由此实现对供电线路绝缘状态的评估。本发明有效评估了环境对供电线路绝缘产生漏电流的影响程度，为判断供电线路绝缘的真实状态提供了参考依据，能够及时发现农村地区电网供电线路的绝缘故障，避免发生触电事故。In order to solve the insensitivity and unreliability of the insulation state evaluation of the power supply line of the existing power system, the present invention first uses the humidity sensor and the leakage sensor to obtain the environmental humidity data and leakage current data of the power supply equipment, and accumulates the environmental humidity and leakage current data of a certain period of time. The current data is then fitted to obtain the relationship curve between the ambient humidity and the leakage current as the correlation characteristic between the leakage current of the power supply line and the ambient humidity. Substitute the newly collected humidity and leakage current values into the fitting equations obtained in the history for verification. When the historical fitting characteristics are met, the line insulation state is in good condition; when the historical fitting characteristics are not met, the insulation of the power supply equipment is judged. abnormal, thereby realizing the evaluation of the insulation state of the power supply line. The invention effectively evaluates the influence degree of the environment on the leakage current of the insulation of the power supply line, provides a reference basis for judging the real state of the insulation of the power supply line, can timely detect the insulation fault of the power supply line of the power grid in rural areas, and avoid electric shock accidents.
附图说明Description of drawings
为了使发明的目的、技术方案和优点更加清楚，下面将结合附图对本发明作进一步的详细描述，其中：In order to make the purpose, technical solutions and advantages of the invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:
图1为本发明公开的基于供电线路漏电流与湿度关系辨识的供电线路绝缘状态评估的流程图；1 is a flowchart of the power supply line insulation state assessment based on the relationship between power supply line leakage current and humidity identification disclosed in the present invention;
图2为利用湿度传感器及漏电流传感器获取目标线路的环境湿度值及漏电流值的原理图；FIG. 2 is a schematic diagram of using the humidity sensor and the leakage current sensor to obtain the ambient humidity value and the leakage current value of the target line;
图3为利用均方最小二乘拟合目标的方法，得到漏电流与湿度之间的拟合方程的示意图。FIG. 3 is a schematic diagram of a fitting equation between leakage current and humidity obtained by using the mean square least squares method of fitting a target.
具体实施方式Detailed ways
下面结合附图对本发明作进一步的详细说明。The present invention will be further described in detail below in conjunction with the accompanying drawings.
如图1所示，基于供电线路漏电流与湿度关系辨识的供电线路绝缘状态评估，包括：As shown in Figure 1, the power supply line insulation status assessment based on the relationship between power supply line leakage current and humidity identification includes:
S1、利用湿度传感器及漏电流传感器获取目标线路的环境湿度值及漏电流值；S1. Use the humidity sensor and the leakage current sensor to obtain the ambient humidity value and leakage current value of the target line;
S2、将目标电路的环境湿度值输入漏电流与湿度之间的关联模型，得到漏电流模型预测值；S2. Input the ambient humidity value of the target circuit into the correlation model between leakage current and humidity, and obtain the predicted value of the leakage current model;
S3、计算漏电流模型预测值与漏电流值的差值，若差值大于预设阈值则判断目标线路绝缘异常，若差值小于或等于预设阈值则判断目标线路绝缘正常。S3. Calculate the difference between the predicted value of the leakage current model and the leakage current value. If the difference is greater than a preset threshold, determine that the insulation of the target line is abnormal, and if the difference is less than or equal to the preset threshold, determine that the insulation of the target line is normal.
附图2所示的三相供电线路的环境湿度与漏电流测量原理图中，其关键部件是漏电流传感器，它由铁芯和绕在铁芯上二次线圈组成检测元件，电源相线和中性线穿过环形铁心构成了互感器的一次线圈N1，缠绕在环形铁芯上的绕组构成了互感器的二次线圈N2，正常情况下，通过漏电流传感器一次线圈电流的相量和为零，二次侧感应电流也为零；当用电设备绝缘损坏发生漏电时，如果人接触带电部分，人体通过大地形成回路，漏电流传感器一次线圈流过电流的向量和不等于零(电气回路有不平衡电流流过)。In the schematic diagram of ambient humidity and leakage current measurement of the three-phase power supply line shown in Figure 2, the key component is the leakage current sensor, which consists of an iron core and a secondary coil wound on the iron core to form a detection element, a power phase wire and The neutral line passes through the toroidal core to form the primary coil N1 of the transformer, and the windings wound on the toroidal core form the secondary coil N2 of the transformer. Under normal circumstances, the phasor sum of the primary coil current through the leakage current sensor is Zero, the induced current on the secondary side is also zero; when the insulation of the electrical equipment is damaged and leakage occurs, if a person touches the live part, the human body forms a loop through the ground, and the vector sum of the current flowing through the primary coil of the leakage current sensor is not equal to zero (the electrical loop has unbalanced current flows).
本发明中，可由湿度传感器测得的实际环境湿度值为W(％)，由漏电流传感器测得的漏电流值为i0(μA)。In the present invention, the actual environmental humidity value measured by the humidity sensor is W (%), and the leakage current value measured by the leakage current sensor is i0 (μA).
此时环境湿度W(％)对应的漏电流模型预测值为i0'(μA)，计算漏电流模型预测值与漏电流值的差值
具体实施时，所述漏电流与湿度之间的关联模型的建立方法包括：During specific implementation, the method for establishing the correlation model between the leakage current and humidity includes:
采集历史环境湿度值集合与历史漏电流值集合，利用均方最小二乘拟合目标的方法，得到漏电流与湿度之间的拟合方程，建立漏电流与湿度之间的关联模型。Collect the set of historical environmental humidity values and the set of historical leakage current values, and use the mean square least squares method to fit the target to obtain a fitting equation between leakage current and humidity, and establish a correlation model between leakage current and humidity.
如图3所示，具体实施时，设漏电流值为yl、环境湿度值为xi，记yl＝f(xi)；As shown in FIG. 3 , in the specific implementation, set the leakage current value as yl and the ambient humidity asxi , and denoteyl =f(xi) ;
f(xi)＝a1r1(x1)+a2r2(x2)+…+amrm(xm) (1)f(xi )=a1 r1 (x1 )+a2 r2 (x2 )+…+am rm (xm ) (1)
r1(x1)至rm(xm)是一组线性无关的函数，aj是待定系数，j＝1,2,3,…,m，m＜n，n是在目标线路的不同地点的测量次数，m是线性无关组中元素个数；r1 (x1 ) to rm (xm ) are a set of linearly independent functions, aj are undetermined coefficients, j=1,2,3,...,m , m<n, n is the difference in the target line The number of measurements of the location, m is the number of elements in the linearly independent group;
记remember
为选取a1,a2,…,am，使J(a1,a2,…,am)最小，利用极值的必要条件
即which is
记remember
R表示参数矩阵，Α表示待定系数矩阵，Y表示漏电流矩阵，此时，方程组(5)可表示为R represents the parameter matrix, A represents the undetermined coefficient matrix, and Y represents the leakage current matrix. At this time, the equation group (5) can be expressed as
RTRA＝RTY (6)RT RA = RT Y (6)
当选取的函数{r1(x),r2(x),…,rm(x)}线性无关时，R列满秩，RTR可逆，于是方程组(6)有唯一解：When the selected function {r1 (x),r2 (x),…,rm (x)} is linearly independent, the R column is full rank, and RT R is invertible, so the equation system (6) has a unique solution:
A＝(RTR)-1RTY (7)A=(RT R)-1 RT Y (7)
得到漏电流与湿度之间的拟合方程。A fitting equation between leakage current and humidity is obtained.
最后说明的是，以上实施例仅用以说明本发明的技术方案而非限制，尽管通过参照本发明的优选实施例已经对本发明进行了描述，但本领域的普通技术人员应当理解，可以在形式上和细节上对其作出各种各样的改变，而不偏离所附权利要求书所限定的本发明的精神和范围。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described with reference to the preferred embodiments of the present invention, those of ordinary skill in the art should Various changes in the above and in the details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.
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