WO2021163888A1 - 电力系统接地故障的检测方法、装置和系统 - Google Patents

电力系统接地故障的检测方法、装置和系统 Download PDF

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Publication number
WO2021163888A1
WO2021163888A1 PCT/CN2020/075738 CN2020075738W WO2021163888A1 WO 2021163888 A1 WO2021163888 A1 WO 2021163888A1 CN 2020075738 W CN2020075738 W CN 2020075738W WO 2021163888 A1 WO2021163888 A1 WO 2021163888A1
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Prior art keywords
multiple nodes
ground fault
power system
nodes
threshold
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PCT/CN2020/075738
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English (en)
French (fr)
Inventor
杜峰
陈维刚
巴特拉·希万西
朱怡
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西门子股份公司
西门子（中国）有限公司
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Application filed by 西门子股份公司, 西门子（中国）有限公司 filed Critical 西门子股份公司
Priority to PCT/CN2020/075738 priority Critical patent/WO2021163888A1/zh
Priority to CN202090001036.0U priority patent/CN218848261U/zh
Priority to DE212020000810.8U priority patent/DE212020000810U1/de
Publication of WO2021163888A1 publication Critical patent/WO2021163888A1/zh

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    • 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
    • G01R31/52—Testing for short-circuits, leakage current or ground faults
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
    • H02H3/167—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass combined with other earth-fault protective arrangements
    • 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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

Definitions

  • the present invention relates to the field of power systems, and in particular to a method, device and system for detecting ground faults in the power system.
  • the power system includes many branches, and each branch is equipped with at least one protection device.
  • the protection device When the line fails, the protection device is used to detect the fault current and cut off the line. However, even if the power system is working normally, even if there is no fault, due to the parasitic capacitance of the devices in the system, there will be residual current on the line. At this time, the protection device may treat the residual current of the parasitic capacitance as a fault current to trigger the protection function. Cut the line. This is what we don't want to see. Especially in the low-voltage power system, it always has a very strong background residual current.
  • the prior art attempts to detect the residual current generated by the parasitic capacitance on the protection line, but it is very difficult to collect the real-time residual current of each node. Due to the high frequency, it is also difficult to sum the residual currents of different nodes in the power system, because the communication speed and process processing requirements are very high.
  • the first aspect of the present invention provides a method for detecting a ground fault in a power system, wherein the power system includes a plurality of branches and their nodes, and each branch is provided with a protection device, characterized in that the detection method includes the following Step: S1, respectively detecting the differential currents of the multiple nodes of the power system and the voltages corresponding to the multiple nodes, the voltage being the potential from the positive line or the negative line to the protection line or the positive line or the negative line to the ground Potential; S2, based on the differential currents and corresponding voltages of the multiple nodes, respectively calculate the average power of the multiple nodes, when the sum of the average power of the multiple nodes exceeds a first threshold, then determine the A ground fault has occurred in multiple nodes.
  • the detection method further includes the following steps: respectively calculating whether the average power of the multiple nodes exceeds a second threshold, and when the average power of two of the nodes exceeds the second threshold, then it is determined that the ground fault occurs In the range between the two nodes.
  • step S2 further includes the step of integrating the product of the differential currents of the multiple nodes and the corresponding voltages to calculate the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes
  • the integral of the product of the current and the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • a second aspect of the present invention provides a system for detecting a ground fault in a power system, including: a processor; and a memory coupled to the processor, the memory having instructions stored therein, and when the instructions are executed by the processor,
  • the electronic device executes an action, the action includes: S1, respectively detecting the differential currents of multiple nodes of the power system and the voltages corresponding to the multiple nodes, and the voltage is from the positive line or the negative line to the protection line S2, calculate the average power of the multiple nodes based on the differential currents and corresponding voltages of the multiple nodes, respectively, when the sum of the average powers of the multiple nodes If a first threshold is exceeded, it is determined that a ground fault has occurred within the range of the multiple nodes.
  • the detection system further includes the following actions: separately calculating whether the average power of the multiple nodes exceeds a second threshold, and when the average power of two of the nodes exceeds the second threshold, then it is determined that the ground fault has occurred In the range between the two nodes.
  • the action S2 further includes: integrating the product of the differential currents of the multiple nodes and the corresponding voltages, and calculating the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes and The integral of the product of the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • a third aspect of the present invention provides a detection device for a ground fault in a power system, including: a detection device that detects differential currents of multiple nodes of the power system and voltages corresponding to the multiple nodes, and the voltage is a positive line Or the potential of the negative line to the protection line or the potential of the positive line or the negative line to the ground; a calculation device that calculates the average power of the multiple nodes based on the differential currents and corresponding voltages of the multiple nodes, when the If the sum of the average powers of the multiple nodes exceeds a first threshold, it is determined that a ground fault has occurred within the range of the multiple nodes.
  • the calculation device is further configured to: respectively calculate whether the average power of the multiple nodes exceeds a second threshold, and when the average powers of two of the nodes exceed the second threshold respectively, it is determined that the ground fault occurs at Within the range between the two nodes.
  • the calculation device is further configured to integrate the product of the differential currents of the multiple nodes and the corresponding voltages to calculate the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes And the integral of the product of the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • the fourth aspect of the present invention provides a computer program product, which is tangibly stored on a computer-readable medium and includes computer-executable instructions that, when executed, cause the computer-executable The method described.
  • a computer-readable medium has computer-executable instructions stored thereon, and the computer-executable instructions, when executed, enable the method according to the first aspect of the present invention.
  • the present invention can accurately detect the ground fault of the power system, and does not misjudge the leakage current caused by the parasitic current in the system as the ground fault current.
  • the invention can also accurately locate the location where the ground fault occurs.
  • Figure 1 is a circuit connection diagram of the power system
  • Fig. 2 is a schematic diagram of the differential current of the nodes of the power system and the integral of the current and voltage.
  • the invention provides a low-voltage power system ground fault protection mechanism, which can calculate whether the current is a resistive component or a capacitive component through the phase angle relationship between the voltage and current of each node, so as to accurately determine whether the suspicious current in the system is the fault current of the ground fault , And accurately locate the ground fault range.
  • the invention is particularly suitable for low-voltage power systems.
  • Figure 1 is a circuit connection diagram of a power system, which is particularly a DC power system.
  • the AC power supply S 2 supplies power to two power supply branches B 1 and B 2 connected in parallel, and the power supply branches B 1 and B 2 respectively have an AC/DC converter (AC/DC converter).
  • the specific power supply branches B 1 and B 2 are also connected in series with a protection device PD 1 and PD 2 respectively .
  • under the protection devices PD 1 and PD 2 are also a first parallel branch, a second parallel branch, and a third parallel branch.
  • the parallel branch and the fourth parallel branch are also a first parallel branch, a second parallel branch, and a third parallel branch.
  • the first parallel branch has a protection device PD 11
  • the second parallel road has a protection device PD 12
  • the third parallel branch has a protection device PD 21
  • the fourth parallel road has a protection device PD 22 .
  • the DC power system also includes a battery source B 3 and a photovoltaic power source B 4 , wherein the battery source B 3 and the photovoltaic power source B 4 are also connected in series with protection devices PD 3 and PD 4, respectively .
  • Under the protection devices PD 3 and PD 4 there are also a fifth parallel branch, a sixth parallel branch and a seventh parallel branch.
  • the fifth parallel branch is connected in series with a protection device PD 31
  • the sixth parallel branch is connected in series with a protection device PD 32
  • the seventh parallel branch is connected in series with a protection device PD 41 .
  • the hybrid circuit breaker provided by the present invention can be applied to protection devices PD 1 , PD 2 , PD 3 , PD 4 , PD 11 , PD 12 , PD 21 , PD 22 , PD 31 , PD 32 , PD 41 Either.
  • the hybrid circuit breaker provided by the present invention can be applied to a DC power system and an AC power system.
  • the first aspect of the present invention provides a method for detecting a ground fault in a power system, wherein the power system includes a plurality of branches and their nodes, each branch is provided with a protection device, and the detection method includes the following steps.
  • step S1 perform step S1 to separately detect the differential currents of the multiple nodes of the power system and the voltages corresponding to the multiple nodes.
  • the voltage is the potential from the positive line or the negative line to the protection line or the positive line or the negative line to the ground. Potential at the end.
  • the differential currents of the first node A, the second node B, and the third node C and their corresponding voltages are detected respectively.
  • the differential current of the first node A is di_PD 1
  • the potential of the positive or negative line of the first node A to the protection line is v pe1
  • the differential current of the second node B is di_PD 2
  • the positive line of the second node B Or the potential of the negative line to the protection line is v pe2
  • the differential current of the third node C is di_PD 3
  • the potential of the positive line or the negative line of the third node C to the protection line is v pe3 .
  • step S2 is executed to calculate the average power of the multiple nodes based on the differential currents and the corresponding voltages of the multiple nodes, and when the sum of the average powers of the multiple nodes exceeds a first threshold, it is determined A ground fault occurred within the range of multiple nodes.
  • the step S2 further includes the step of integrating the product of the differential currents of the multiple nodes and the corresponding voltages to calculate the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes The integral of the product of the current and the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • the method includes the following steps: separately calculating whether the average power of the multiple nodes exceeds a second threshold, and when the average power of two of the nodes exceeds the second threshold respectively, it is determined that the ground fault occurs between the two nodes In the range.
  • the average power jumps in a certain period of time, that is, changes, and once the change exceeds a predetermined threshold, it is considered abnormal.
  • a predetermined threshold and if the average power is too large, it is considered a fault.
  • a plurality of protection devices are provided with communication lines, and the communication lines are shown by dotted lines as shown in FIG. 1.
  • a control device is connected to the communication line for implementing the present invention.
  • the curve shown in Figure 2 the abscissa is time t, the ordinate is the differential current di_PD 1 of the first protection device, the differential current di_PD 2 of the second protection device, and the currents of the first protection device and the second protection device.
  • the differential current di_PD 1 of the first protection device and the differential current di_PD 2 of the second protection device cannot accurately detect whether the suspicious current in the system is a leakage current or a fault current caused by a ground fault.
  • the sum of the current and voltage integration of the first protection device and the second protection device InteP 1 +InteP 2 and the jump ⁇ InteP of the current and voltage integration can detect the fault current. This is sufficient to illustrate the superiority of the present invention.
  • a second aspect of the present invention provides a system for detecting a ground fault in a power system, including: a processor; and a memory coupled to the processor, the memory having instructions stored therein, and when the instructions are executed by the processor,
  • the electronic device executes an action, the action includes: S1, respectively detecting the differential currents of multiple nodes of the power system and the voltages corresponding to the multiple nodes, and the voltage is from the positive line or the negative line to the protection line S2, calculate the average power of the multiple nodes based on the differential currents and corresponding voltages of the multiple nodes, respectively, when the sum of the average powers of the multiple nodes If a first threshold is exceeded, it is determined that a ground fault has occurred within the range of the multiple nodes.
  • the detection system further includes the following actions: separately calculating whether the average power of the multiple nodes exceeds a second threshold, and when the average power of two of the nodes exceeds the second threshold, then it is determined that the ground fault has occurred In the range between the two nodes.
  • the action S2 further includes: integrating the product of the differential currents of the multiple nodes and the corresponding voltages, and calculating the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes and The integral of the product of the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • the calculation device is further configured to: respectively calculate whether the average power of the multiple nodes exceeds a second threshold, and when the average powers of two of the nodes exceed the second threshold respectively, it is determined that the ground fault occurs in Within the range between the two nodes.
  • the calculation device is further configured to integrate the product of the differential currents of the multiple nodes and the corresponding voltages to calculate the average powers of the multiple nodes respectively, wherein the differential currents of the multiple nodes And the integral of the product of the corresponding voltage is:
  • di_PD n is the differential current
  • v n is the corresponding voltage
  • the fourth aspect of the present invention provides a computer program product, which is tangibly stored on a computer-readable medium and includes computer-executable instructions that, when executed, cause the computer-executable The method described.
  • a computer-readable medium has computer-executable instructions stored thereon, and the computer-executable instructions, when executed, enable the method according to the first aspect of the present invention.
  • the present invention can accurately detect the ground fault of the power system, and does not misjudge the leakage current caused by the parasitic current in the system as the ground fault current.
  • the invention can also accurately locate the location where the ground fault occurs.

Abstract

一种电力系统接地故障的检测方法、装置和系统，其中，电力系统包括复数个支路及其节点，每个支路设置有一个保护装置，检测方法包括如下步骤：S1，分别检测电力系统的多个节点的差分电流以及多个节点对应的电压，电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；S2，基于多个节点的差分电流和对应的电压，分别计算多个节点的平均功率，当多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。本方法能够准确判断电力系统接地故障，并且定位接地故障发生位置。

Description

电力系统接地故障的检测方法、装置和系统 技术领域
本发明涉及电力系统领域，尤其涉及电力系统接地故障的检测方法、装置和系统。
背景技术
电力系统包括很多支路，每个支路都会设置至少一个保护装置，当线路发生故障时，保护装置用于检测故障电流并且切断线路。然而，即使电力系统在正常工作时，即使没有发生故障，由于系统中器件寄生电容的存在，线路上会有剩余电流，此时保护装置就可能将寄生电容的剩余电流当成故障电流从而触发保护功能切断线路。这是我们不希望看到的。特别是在低压电力系统，其总是具有非常强的背景剩余电流存在。
为了解决上述问题，现有技术尝试通过在保护线上把寄生电容产生的剩余电流检测出来，然而对每个节点的实时剩余电流进行采集非常难。由于高频率，对电力系统不同节点的剩余电流求和也很难，因为对通信速度和过程处理要求非常高。
发明内容
本发明第一方面提供了电力系统接地故障的检测方法，其中，所述电力系统包括复数个支路及其节点，每个支路设置有一个保护装置，其特征在于，所述检测方法包括如下步骤：S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
进一步地，所述检测方法还包括如下步骤：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超 过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
进一步地，所述步骤S2还包括如下步骤：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
本发明第二方面提供了电力系统接地故障的检测系统，包括：处理器；以及与所述处理器耦合的存储器，所述存储器具有存储于其中的指令，所述指令在被处理器执行时使所述电子设备执行动作，所述动作包括：S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
进一步地，所述检测系统还包括如下动作：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
进一步地，所述动作S2还包括：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
本发明第三方面提供了电力系统接地故障的检测装置，包括：检测装置，其分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；计算装置，其基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
进一步地，所述计算装置还用于：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
进一步地，所述计算装置还用于：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
本发明第四方面提供了计算机程序产品，所述计算机程序产品被有形地存储在计算机可读介质上并且包括计算机可执行指令，所述计算机可执行指令在被执行时使本发明第一方面所述的方法。
本发明第五方面计算机可读介质，其上存储有计算机可执行指令，所述计算机可执行指令在被执行时使本发明第一方面所述的方法。
本发明能够准确检测电力系统的接地故障，而不会将系统中寄生电流带来的漏电流误判为接地故障电流。本发明还能够准确定位接地故障发生的位置。
附图说明
图1是电力系统的电路连接图；
图2是电力系统的节点的差分电流及其电流电压积分的曲线示意图。
具体实施方式
以下结合附图，对本发明的具体实施方式进行说明。
本发明提供了低压电力系统接地故障保护机制，能够通过每个节点电压和电流的相角关系算出来电流是阻性成分还是容性成分，从而精确判断系统中可疑电流是否为接地故障的故障电流，并且对接地故障范围进行准确定位。本发明尤其适用于低压电力系统。
图1是电力系统的电路连接图，其特别地为一个直流电力系统。其中，交流电源S 2为并联的两个电源支路B 1和B 2供电，所述电源支路B 1和B 2分别具有一个交流直流转换器(AC/DC converter)。具体电源支路B 1和B 2还分别串联有一个保护装置PD 1和PD 2，其中，在保护装置PD 1 和PD 2之下还具有第一并联支路、第二并联支路、第三并联支路和第四并联支路。其中第一并联支路具有一个保护装置PD 11，第二并联之路具有一个保护装置PD 12，第三并联支路具有一个保护装置PD 21，第四并联之路具有一个保护装置PD 22。在直流电力系统还包括一个电池源B 3和一个光伏电源B 4，其中电池源B 3和光伏电源B 4还分别串联有保护装置PD 3和PD 4。在保护装置PD 3和PD 4之下还具有第五并联支路第六并联支路和第七并联支路。其中，第五并联支路串联有一个保护装置PD 31，第六并联支路串联有一个保护装置PD 32，第七并联支路串联有一个保护装置PD 41。示例性地，本发明提供的混合断路器可以应用于保护装置PD 1、PD 2、PD 3、PD 4、PD 11、PD 12、PD 21、PD 22、PD 31、PD 32、PD 41中的任一个。需要说明的是，本发明提供的混合断路器可以应用于直流电力系统以及交流电力系统。
本发明第一方面提供了一种电力系统接地故障的检测方法，其中，所述电力系统包括复数个支路及其节点，每个支路设置有一个保护装置，所述检测方法包括如下步骤。
首先执行步骤S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位。如图1所示，例如，在本实施例中，分别检测第一节点A、第二节点B、第三节点C的差分电流及其对应的电压。其中，第一节点A的差分电流为di_PD 1，第一节点A的正极线或负极线到保护线的电位为v pe1，第二节点B的差分电流为di_PD 2，第二节点B的正极线或负极线到保护线的电位为v pe2，第三节点C的差分电流为di_PD 3，第三节点C的正极线或负极线到保护线的电位为v pe3。
然后执行步骤S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。优选地，所述步骤S2还包括如下步骤：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
具体地，第一节点A的电流电压积分为InteP 1＝∫(di_PD 1*v 1)dt，其中v 1为第一节点A的正极线或负极线到保护线的电位为v pe1，第二节点B的电流电压积分为InteP 2＝∫(di_PD 2*v 2)dt，其中v 2为第二节点B的正极线或负极线到保护线的电位为v pe2，第三节点C的电流电压积分为InteP 3＝∫(di_PD 3*v3dt，其中v3为第三节点C的正极线或负极线到保护线的电位为vpe3。如果第一节点A的电流电压积分为InteP 1＝∫(di_PD 1*v 1)dt，第二节点B的电流电压积分为InteP 2＝∫(di_PD 2*v 2)dt以及第三节点C的电流电压积分为InteP 3＝∫(di_PD 3*v 3)dt的和超过一个第一阈值，则判断所述第一节点A、第二节点B和第三节点C范围内发生了接地故障。其中，电流电压的乘积的积分体现了电流电压相角关系，能够获得幅值，电压和电流相乘得出瞬时功率，做积分是这个时间内的平均功率。
优选地，虽然根据上述步骤可以确认所述第一节点A、第二节点B和第三节点C范围内发生了接地故障，还需要对接地故障的具体位置进行定位，因此，在步骤S2后还包括如下步骤：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
具体地，分别用第一节点A的电流电压积分为InteP 1＝∫(di_PD 1*v 1)dt，第二节点B的电流电压积分为InteP 2＝∫(di_PD 2*v 2)dt以及第三节点C的电流电压积分为InteP 3＝∫(di_PD 3*v 3)dt与第二阈值比较，假设其中的第一节点A的电流电压积分为InteP 1＝∫(di_PD 1*v 1)dt，第二节点B的电流电压积分为InteP 2＝∫(di_PD 2*v 2)dt大于第二阈值，如图1所示，则认为接地故障F发生在第一节点A和第二节点B之间。
其中，平均功率在某个时间段的跳变，也就是变化，一旦变化超过了预定阈值则认为是不正常的。设定一个预定阈值，平均功率如果大到一定程度就认为是故障。
此外，如图1所示，多个保护装置设置有通信线，通讯线如图1所示的虚线所示。通讯线上连接有控制装置，用于执行本发明。
如图2所示的曲线，其横坐标为时间t，纵坐标依次为第一保护装置的差分电流di_PD 1、第二保护装置的差分电流di_PD 2、第一保护装置和第二保护装置的电流电压积分的和InteP 1+InteP 2、电流电压积分的跳变ΔInteP。如图2可知，从第一保护装置的差分电流di_PD 1和第二保护装置的差分电流di_PD 2并不能确切检测出系统中的可疑电流为漏电流还是接地故障带来的故障电流，然而从利用本发明，第一保护装置和第二保护装置的电流电压积分的和InteP 1+InteP 2和电流电压积分的跳变ΔInteP均可以检测出故障电流。这足以说明本发明的优越性。
本发明第二方面提供了电力系统接地故障的检测系统，包括：处理器；以及与所述处理器耦合的存储器，所述存储器具有存储于其中的指令，所述指令在被处理器执行时使所述电子设备执行动作，所述动作包括：S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
进一步地，所述检测系统还包括如下动作：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
进一步地，所述动作S2还包括：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
本发明第三方面提供了电力系统接地故障的检测装置，包括：检测装置，其分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；计算装置，其基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，当所述多 个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
进一步地，所述计算装置还用于：分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
进一步地，所述计算装置还用于：对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
InteP＝∫(di_PD n*v n)dt
其中，di_PD n为所述差分电流，v n为所述对应的电压。
本发明第四方面提供了计算机程序产品，所述计算机程序产品被有形地存储在计算机可读介质上并且包括计算机可执行指令，所述计算机可执行指令在被执行时使本发明第一方面所述的方法。
本发明第五方面计算机可读介质，其上存储有计算机可执行指令，所述计算机可执行指令在被执行时使本发明第一方面所述的方法。
本发明能够准确检测电力系统的接地故障，而不会将系统中寄生电流带来的漏电流误判为接地故障电流。本发明还能够准确定位接地故障发生的位置。
尽管本发明的内容已经通过上述优选实施例作了详细介绍，但应当认识到上述的描述不应被认为是对本发明的限制。在本领域技术人员阅读了上述内容后，对于本发明的多种修改和替代都将是显而易见的。因此，本发明的保护范围应由所附的权利要求来限定。此外，不应将权利要求中的任何附图标记视为限制所涉及的权利要求；“包括”一词不排除其它权利要求或说明书中未列出的装置或步骤；“第一”、“第二”等词语仅用来表示名称，而并不表示任何特定的顺序。

Claims (11)

  1. 电力系统接地故障的检测方法，其中，所述电力系统包括复数个支路及其节点，每个支路设置有一个保护装置，其特征在于，所述检测方法包括如下步骤：
    S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；
    S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，
    当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
  2. 根据权利要求1所述的电力系统接地故障的检测方法，其特征在于，所述检测方法还包括如下步骤：
    分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
  3. 根据权利要求1所述的电力系统接地故障的检测方法，其特征在于，所述步骤S2还包括如下步骤：
    对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
    InteP＝∫(di_PD n*v n)dt
    其中，di_PD n为所述差分电流，v n为所述对应的电压。
  4. 电力系统接地故障的检测系统，包括：
    处理器；以及
    与所述处理器耦合的存储器，所述存储器具有存储于其中的指令，所述指令在被处理器执行时使所述电子设备执行动作，所述动作包括：
    S1，分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；
    S2，基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，
    当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
  5. 根据权利要求4所述的电力系统接地故障的检测系统，其特征在于，所述检测系统还包括如下动作：
    分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
  6. 根据权利要求4所述的电力系统接地故障的检测系统，其特征在于，所述动作S2还包括：
    对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
    InteP＝∫(di_PD n*v n)dt
    其中，di_PD n为所述差分电流，v n为所述对应的电压。
  7. 电力系统接地故障的检测装置，包括：
    检测装置，其分别检测所述电力系统的多个节点的差分电流以及所述多个节点对应的电压，所述电压为正极线或负极线到保护线的电位或者正极线或负极线到地端的电位；
    计算装置，其基于所述多个节点的差分电流和对应的电压，分别计算所述多个节点的平均功率，
    当所述多个节点的平均功率的和超过一个第一阈值，则判断所述多个节点范围内发生了接地故障。
  8. 根据权利要求7所述的电力系统接地故障的检测装置，其特征在于，所述计算装置还用于：
    分别计算所述多个节点的平均功率是否超过一个第二阈值，当其中两个节点的平均功率分别超过第二阈值，则判断所述接地故障发生在所述两个节点之间的范围内。
  9. 根据权利要求1所述的电力系统接地故障的检测装置，其特征在于，所述计算装置还用于：
    对所述多个节点的差分电流和对应的电压的乘积做积分，分别计算所述多个节点的平均功率，其中，所述多个节点的差分电流和对应的电压的乘积的积分为：
    InteP＝∫(di_PD n*v n)dt
    其中，di_PD n为所述差分电流，v n为所述对应的电压。
  10. 计算机程序产品，所述计算机程序产品被有形地存储在计算机可读介质上并且包括计算机可执行指令，所述计算机可执行指令在被执行时使至少一个处理器执行根据权利要求1至3中任一项所述的方法。
  11. 计算机可读介质，其上存储有计算机可执行指令，所述计算机可执行指令在被执行时使至少一个处理器执行根据权利要求1至3中任一项所述的方法。
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