WO2015139587A1 - 一种配电网区域接地故障检测方法及一种配电网接地故障区域定位系统 - Google Patents

一种配电网区域接地故障检测方法及一种配电网接地故障区域定位系统 Download PDF

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Publication number
WO2015139587A1
WO2015139587A1 PCT/CN2015/074276 CN2015074276W WO2015139587A1 WO 2015139587 A1 WO2015139587 A1 WO 2015139587A1 CN 2015074276 W CN2015074276 W CN 2015074276W WO 2015139587 A1 WO2015139587 A1 WO 2015139587A1
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ground
area
relative
distribution network
region
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PCT/CN2015/074276
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English (en)
French (fr)
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田京涛
田广宁
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田京涛
田广宁
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Publication of WO2015139587A1 publication Critical patent/WO2015139587A1/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
    • G01R31/08—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
    • 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

Definitions

  • the invention relates to ground fault detection in a distribution network area and ground fault area location in a distribution network.
  • medium voltage power distribution systems generally use small current grounding systems, and some low voltage power distribution systems with special requirements also use small resistance grounding systems.
  • the neutral point through the arc suppression coil grounding method can reduce the current flowing through the ground fault point when the ground fault occurs in the distribution network, which is beneficial to the continuous and stable power supply of the distribution network, but the compensation current generated by the arc suppression coil is added.
  • the rule of grounding line selection using the amplitude and phase of zero-sequence current is widely used in the early days. For this reason, relevant researchers at home and abroad have researched and developed various methods of grounding and positioning methods, but so far, the practical application effect Not ideal, especially for the selection and positioning of high-resistance ground faults, there is no good solution.
  • grounding line selection Due to the problems in the positioning of the grounding line selection of the small current grounding system, some distribution networks in China have adopted the neutral point through the small resistance grounding system. The purpose is to remove the faulty line in time when the system has a ground fault; but the neutral point When a high-resistance grounding fault occurs through a small-resistance grounding system, since the fault current is small and the protection may be rejected, there is also a problem of grounding line selection. Grounding line selection has become a bottleneck in improving power supply quality of distribution networks, and there is an urgent need for more accurate and effective grounding line selection methods.
  • the object of the present invention is to provide a ground fault detection method for a distribution network area, and to determine whether there is a ground fault in a region within an area when a ground fault occurs in the distribution network.
  • the invention also provides a grounding fault area localization system for distribution network, which utilizes the ground fault detection method of the distribution network area to realize the ground fault area localization function of the distribution network.
  • the method for ground fault of the distribution network area of the present invention is as follows:
  • Delineating an area in the distribution network which may include only one device or a line of lines, or may include several devices and several lines connected and adjacent;
  • the relative ground voltage of the region using the region Area to ground current The B EA0 , B EB0 , and B EC0 are electrically connected to the third area to determine whether there is a ground fault in the area.
  • the regional three relative ground voltage Area to ground current The following relationship exists between the electrical conductivity B EA , B EB , B EC , and the regional relative conductance G EA , G EB , and G EC in comparison with the regional three:
  • Each set of data can form an equation for solving the three regional susceptances B EA0 , B EB0 , B EC0 .
  • the regional three relative susceptances B EA0 , B EB0 , B EC0 of the region can be obtained.
  • area three is relatively Voltage Area to ground capacitance current
  • the area-to-ground current of the area Equal to the area of the region to the capacitive current If there is a ground fault in the area, then the area to ground current Capacitance current from area to ground And the ground fault current flowing into the earth through the ground fault point; the region-to-ground current of the region due to the addition of the ground fault current Capacitance current to the area from the region It is no longer equal; it can be judged whether there is a ground fault in the area.
  • the regional three relative susceptance B EA , B EB , B EC if there is no ground fault in the area, the area to ground current of the area Equal to the area of the region to the capacitive current
  • the detected area 3 relative to ground susceptance B EA , B EB , B EC and the previously measured area 3 relative to the ground contact B EA0 , B EB0 , B EC0 should be close; if there is a ground fault in the area range due to fault current Join, the area of the region to the ground current Capacitance current to the area from the region No longer equal, there should be a large difference between the detected regional susceptance B EA , B EB , B EC and the previously measured region 3 relative to the ground contact B EA0 , B EB0 , B EC0 ; It is determined whether there is a ground fault in the area.
  • the area-to-ground current of the area Equal to the area of the region to the capacitive current If there is a ground fault in the area, then the area to ground current Capacitance current from area to ground And the fault current flowing into the earth from the ground fault point; at this time, the relative ground voltage of the region three can be utilized Area to ground current Relative to the regional three, the relationship between the B EA , B EB , B EC and the regional three relative conductance G EA , G EB , G EC , online measurement area three relative ground conductance G EA , G EB , G EC , According to the measurement result, it is judged whether there is a ground fault in the area.
  • the area of the area is three relative to ground voltage Area to ground current
  • the relationship between the electrical conductances B EA , B EB , B EC , and the regional relative conductance G EA , G EB , and G EC is compared with the third region:
  • the relative ground voltage of the region three for the region The measurement method is: the area of the region can be measured in the region three relative voltage It is also possible to measure the three relative ground voltages of the three-phase conductor in electrical connection with the three-phase line in the area outside the area. Calculate the relative ground voltage of the area in the area using the measurement results outside the area It is also possible to directly measure the measurement outside the region as the relative voltage of the region three in the region. Use it.
  • the detection method is: installing a current detecting device at a boundary between the region and other regions, detecting a zero-sequence current flowing into the region from other regions by using the current detecting device, and zero-sequence current flowing through the zero-sequence current flowing into the region.
  • the direction vectors flowing into the region are added to obtain the region-to-ground current of the region
  • the detection method is: in the range of the region, there is a device ground between the phase conductors and the earth, the device ground and the phase conductors are insulated, and the device ground and the earth are also insulated, and the equipment ground can be
  • the ground current is connected to the ground through one or more grounding lines; the current flowing through the grounding lines between the ground and the ground is detected by the current detecting device, and the current flowing through the grounding lines is added by the vector flowing into the ground.
  • Area-to-ground current of the region can be obtained
  • the method is matched with the detection of the relative parameters of the region three, and the voltage of each of the three relative grounds is changed once. Measuring the relative ground voltage of the region three of the region at a time And regional to ground current Forming a linearly irrelevant set of equations for solving the three relative parameters of the region of the region, by solving the equation, obtaining the relative parameters of the region three of the region, thereby realizing the detection of the relative parameters of the region three at any time, and improving The purpose of detection accuracy.
  • the method of artificially adjusting the relative ground voltage of the distribution network may be to ground the distribution network one phase; the grounding of the distribution network may be grounded through a resistor, an inductor or a capacitor; it may be in the neutral point or artificial of the distribution network. Adding a resistor, inductor or capacitor between the ground and the ground; it may be to change the impedance of the resistor, inductor or capacitor connected between the neutral point of the distribution network or the artificial neutral point and the ground; Adding an offset power supply between the network neutral point or the artificial neutral point and the ground causes the neutral point of the distribution network to shift to the ground voltage; it may be that the output voltage of the transformer is neutrally biased by adjusting the tap changer of the transformer.
  • the shift may be performed by using a combination of the above methods to adjust the relative ground voltage of the distribution network.
  • grounding fault area localization system of the distribution network of the invention is as follows:
  • the distribution network ground fault area localization system divides different areas in the distribution network, and according to the foregoing method or several methods in the ground fault detection method of the distribution network area, respectively detects the range of the area for each area Whether there is a ground fault in the area, determine which area the ground fault is in, or determine that the ground fault is outside the detected areas, so as to realize the ground fault area location function of the distribution network.
  • the distribution network ground fault area positioning system comprises a voltage detecting device, a current detecting device, a voltage offset device and a distribution network ground fault area locating device; and the distributed current detecting device is used to delimit different regions in the distribution network Detecting the relative ground voltage of the three regions of each region by the voltage detecting device The current detecting device detects the current of each current detecting point; the detection data from the voltage detecting device and the current detecting device is received by the distribution network ground fault area locating device, and the relative ground voltage of each region is obtained after processing.
  • the voltage offset device can adjust three relative ground voltages of the distribution network according to the instruction of the ground fault area locating device of the distribution network; the distribution network ground fault area locating system is according to one of the foregoing ground fault detection methods for the distribution network area A method or a plurality of methods respectively detect whether there is a ground fault in the area of the area for each area, thereby realizing the positioning function of the ground fault area of the distribution network.
  • the voltage offset device may be a device capable of grounding the distribution network in one phase; it may be a device capable of grounding a phase of the distribution network through a resistor, a reactor or a capacitor; it may be a resistor, a reactance a device or capacitor connected in series between a neutral point of the power distribution network or an artificial neutral point to the ground; it may be capable of being connected in series between a neutral point of the power distribution network or an artificial neutral point to the ground a device in which the impedance of a resistor, reactor or capacitor is changed; it may be a neutral point connected to the distribution network or a pressure regulating device between the artificial neutral point and the ground, which enables the neutral point of the power distribution network
  • the ground voltage is offset; it may be a three-phase power source capable of outputting a three-phase symmetrical voltage and capable of adjusting three relative ground voltages; or a combination of the above devices.
  • the voltage offset device further includes a voltage offset control device that controls the voltage offset device, the voltage offset control device being capable of controlling the voltage offset device to change according to an instruction of a distribution network ground fault region locating device Three relative ground voltages of the distribution network With the distribution network ground fault area positioning system to achieve the distribution network ground fault area location function.
  • the distribution network ground fault area positioning system further comprises a signal output device, wherein the signal output device can transmit the area-to-ground parameter to the switch device in the distribution network; or the signal output device transmits the area-to-ground parameter to the supply device.
  • the electric automation system; or the regional output parameter is transmitted to the upper computer system by the signal output device; or the signal output device transmits the information of the area where the ground fault is located to the switch device in the power supply and distribution network, and the ground fault is isolated by the switch device.
  • the signal output device transmits the information of the area where the ground fault is located to the power distribution automation system, where the power supply automation system isolates the area where the ground fault exists; or the signal output device transmits the information of the area where the ground fault is located to the upper computer system
  • the operation of the relevant equipment is arranged by the operation personnel of the power distribution network to isolate the area where the ground fault exists.
  • the distribution network ground fault area localization system further includes a signal input device that can receive information from the upper computer system; or receive information from the distribution automation system; or receive information from the switching device;
  • the distribution network ground fault area localization system can adjust relevant data according to the received information, or adjust the internal working state according to the received information, or perform related operations according to the received information.
  • the system can measure the regional-to-ground parameters of the distribution network online, which can be used to measure the capacitance current of the distribution network online, and provide a basis for adjusting the gear position of the arc-suppression coil; it can be used to find the area where the three relative parameters are unbalanced. It can guide the system three-phase voltage unbalance treatment; it can be used for small current grounding line selection; it can be used for ground fault area localization; the measured ground parameters can also be used for the fixed value calculation of the distribution network relay protection and the ground fault point location calculation.
  • the method of positioning the ground fault area based on the measurement area to ground parameters, participating in the calculation of the three relative ground voltages, the area-to-ground current and the area-to-ground parameters of the area, and which neutral point grounding the system uses.
  • the way does not matter. Therefore, the present invention is not only applicable to various small current grounding systems, but also effective for a neutral point via a small resistance grounding system; for a neutral point via a small resistance grounding system, if an appropriate method is used to adjust the neutral point to ground voltage, It is also possible to implement regional-to-ground parameter measurement and ground fault area location, especially in the selection and positioning of high-resistance ground faults.
  • the ground fault area localization method of the present invention is also applicable. In the area where there is a ground fault, there will be an abnormal change of the current to the ground. Because each ground is judged by ground fault, it is natural to find all the areas where the ground fault exists.
  • the neutral point voltage offset is small, the fault current is small, and the influence of the regional three-phase line-to-ground parameter imbalance on the amplitude and phase of the area-to-ground current increases; the ground fault of the present invention
  • the regional positioning method considers the influence of the three-phase line on the ground parameters, and can improve the regional positioning accuracy of the high-resistance ground fault. Increasing the accuracy of the three relative ground voltages and the area-to-ground current is beneficial to improving the success rate of the positioning of the high-resistance ground fault area.
  • the ground fault area positioning method of the present invention may be adversely affected, and the arc should be extinguished. If filtering measures are taken in the voltage and current detection sections, the ground fault judgment effect can be improved. For the problem of arc grounding line selection, some other technical solutions can achieve good results. Consider using a variety of grounding line positioning techniques for comprehensive judgment, in order to achieve better results.
  • the system has a self-test function. Since it is calculated and judged based on detecting the relative ground voltage and the area-to-ground current, if the wiring of the voltage transformer and the zero-sequence current transformer is faulty or the related equipment fails, it can be found in the calculation process.
  • Fig. 2 One of the simplified models of centralized grounding parameters in the distribution network area
  • FIG. 4 Schematic diagram of the basic principle of the grounding fault determination method in the distribution network area
  • FIG. 5 Schematic diagram of the basic principle of the grounding fault area location system of the distribution network.
  • Figure 6 is a schematic diagram of the principle of adjusting three relative ground voltages by using a grounding resistor
  • FIG. 7 Schematic diagram of adjusting the relative ground voltage by using a grounding reactor
  • Figure 8 is a schematic diagram of the principle of adjusting the relative ground voltage by using a grounding switch
  • Figure 9 is a schematic diagram of the principle of adjusting the neutral point to ground voltage by using a voltage regulating device connected in series between the neutral point and the ground.
  • FIG. 10 is a schematic diagram of the positioning principle of the ground fault area of the distribution network provided with the ground voltage detecting device for the distribution electric room
  • FIG 11 Schematic diagram of the positioning principle of the ground fault area of the ring network
  • FIG. 12 Application schematic diagram of grounding fault area localization of small resistance grounding system
  • Figure 13 is a schematic diagram of the principle of the grounding fault area localization system of the distribution network with the upper computer system
  • FIG.14 Schematic diagram of simulation test of grounding fault detection method in distribution network area and grounding fault area location of distribution network
  • Figure 1 is a model for concentrating parameters of the distribution network area.
  • R A , R B , and R C are the resistances of the three-phase line
  • L A , L B , and L C are the self-inductances of the three-phase lines
  • L AB , L AC , and L BC are the mutual inductances of the three-phase lines
  • C AB , C AC , C BC are three-phase line-to-line capacitance
  • R EA , R EB , and R EC are three-phase line-to-ground resistances
  • C EA , C EB , and C EC are three-phase line-to-ground capacitances.
  • Figure 2 is one of the simplified models for centralized ground-to-ground parameters in the distribution network area.
  • phase conductors of each phase have only three relative ground resistances R EA , R EB , R EC and ground capacitances C EA , C EB , and C EC .
  • Figure 3 is the second simplified model of centralized ground-to-ground parameters in the distribution network area.
  • FIG. 4 is a schematic diagram of the basic principle of the method for judging the ground fault of the distribution network area.
  • the regional-to-ground parameters include the regional three relative ground conductances G EA , G EB , G EC , and the regional three relative tones B EA , B EB , B EC ;
  • the basic equipment that needs to be configured to determine whether there is a ground fault in the area includes a voltage transformer PT, a zero-sequence current transformer CT1 and CT2, a voltage detecting module, a current detecting module, and a signal processing device;
  • the secondary connection of the voltage detecting module and the voltage transformer PT constitutes a voltage monitoring device, and detects the relative ground voltage of the region three
  • the current detecting module is connected with the zero-sequence current transformer to form a current detecting device, and detects the zero-sequence current flowing through the two zero-sequence current transformers CT1 and CT2.
  • the signal processing device Receiving, by the signal processing device, the relative ground voltage of the region three detected from the voltage detecting device And zero sequence current from the current detection device with Signal processing device with According to the direction vector of the current flowing to the inside of the region, the region-to-ground current of the region to be detected is obtained.
  • the signal processing device passes the voltage to the ground three And regional to ground current Processing and calculation are performed to determine whether there is a ground fault in the area.
  • the relative ground voltage of the region three will be detected at the same time.
  • the region III relative conductance G EA , G EB , G EC and the region 3 relative to the susceptance B EA , B EB , B EC as an unknown amount can form the solution region three relative ground conductance G EA , G EB , G EC and region 3 are relatively electrically charged to the equations of B EA , B EB , B EC ;
  • the relative ground voltage of the area three can be changed.
  • the area three relative ground voltage is changed Measuring the relative ground voltage of the area three
  • An equation for solving an unknown region-to-ground parameter can be formed; by repeating this process, a system of equations for solving an unknown region-to-ground parameter that satisfies linear independence can be obtained; by solving the equations, an unknown region-to-ground parameter can be calculated. .
  • the vector equation for solving the relative parameters of the region three can be:
  • ⁇ B , ⁇ C , and ⁇ E are the relative ground voltages of B, respectively C relative ground voltage And regional to ground current Hysteresis A relative ground voltage Angle.
  • the region-to-ground resistive current is much smaller than the region-to-ground capacitive current, and the resistive current can be ignored, and the regional three relative ground conductances G EA0 , G EB0 , G EC0 is 0, the aforementioned regional three relative ground voltage And regional to ground current
  • the conductance G EA , G EB , G EC and the region 3 relative to the ground three B EA , B EB , B EC as opposed to the region III :
  • the relative ground voltage of the area three can be changed.
  • An equation for solving the three regional susceptances B EA , B EB , and B EC can be formed; by repeating this process, an equation for satisfying the linear irrelevant needs of the three regional susceptances B EA , B EB , and B EC can be obtained. Group; by solving the equations, we can calculate the relative regional susceptance B EA , B EB , B EC in the region range.
  • ⁇ B , ⁇ C , and ⁇ E are the relative ground voltages of B, respectively C relative ground voltage And regional to ground current Hysteresis A relative ground voltage Angle. These two scalar equations can be used to calculate the regional relative susceptance B EA , B EB , B EC .
  • the area 3 relative to ground susceptance B EA , B EB , B EC measured by the method can be saved as the parameter value B EA0 , B EB0 of the area 3 relative to the ground of the area.
  • B EC0 this parameter value can be used as a line parameter in the regional ground fault detection.
  • this method can be used to measure the relative grounding susceptance B EA , B EB , B EC of the three regions, and compare the measurement results with B EA0 , B EB0 , B EC0 to determine whether There is a criterion for a ground fault.
  • the relative ground voltage of the area three can be changed.
  • An equation for solving the relative conductance G EA , G EB , G EC of the region 3 can be formed; by repeating this process, the equations satisfying the linear independent need can be obtained; by solving the equations, the region 3 can be calculated Conductance G EA , G EB , G EC .
  • ⁇ B , ⁇ C , and ⁇ E are the relative ground voltages of B, respectively C relative ground voltage And regional to ground current Hysteresis A relative ground voltage Angle.
  • the calculated region three relative ground conductances G EA , G EB , and G EC can be used to determine whether there is a ground fault criterion in the region.
  • phase-to-ground conductances G EA0 and G EB0 of the A and B phases can be set to 0, and the aforementioned regional three relative ground voltages And regional to ground current Relationship with regional-to-ground parameters:
  • the relative ground voltage of the area three can be changed.
  • An equation for solving the region C relative to the ground conductance G EC and the region three relative to the ground ferroelectric B EA , B EB , B EC can be formed; repeating this process, the solution region C can be obtained relative to the ground conductance G EC and the region three relative geoelectric
  • the system of B EA , B EB , B EC satisfies the linearly independent equations; by solving the equations, the regional conductance G EC and the regional three relative susceptance B EA , B EB , B EC can be calculated.
  • the vector equation for solving the region C relative to the ground conductance G EC and the region three relative to the B EA , B EB , B EC can be:
  • ⁇ B , ⁇ C , and ⁇ E are the relative ground voltages of B, respectively C relative ground voltage And regional to ground current Hysteresis A relative ground voltage Angle.
  • the calculated region C relative to the ground conductance G EC can be used to determine whether there is a ground fault in the region. This method can also be used to measure the parameter values B EA0 , B EB0 , B EC0 of the region 3 relative to the susceptance of the region.
  • the offline or online measurement area 3 is relatively electrically charged B EA0 , B EB0 , B EC0 ; when a ground fault occurs in the distribution network, it is first determined which phase has a ground fault;
  • phase-to-ground conductances G EA0 and G EB0 of the A and B phases can be set to 0, and the aforementioned regional three relative ground voltages And regional to ground current Relationship with regional-to-ground parameters:
  • the vector equation for solving the region C relative to the conductance G EC can be:
  • ⁇ B , ⁇ C , and ⁇ E are the relative ground voltages of B, respectively C relative ground voltage And regional to ground current Hysteresis A relative ground voltage Angle.
  • the calculated region C relative to the ground conductance G EC can be used to determine whether there is a ground fault in the region.
  • Relative ground voltage for a region of three regions The measurement method is: three relative ground voltages can be measured in the area It is also possible to measure the three relative ground voltages of the three-phase conductors that are electrically connected to the three-phase lines in the area outside the area. Calculate the three relative ground voltages in the area using the measurement results outside the area Or directly take the measurement results outside the area as the three relative ground voltages in the area Use it.
  • the equipment ground and the phase conductors are insulated, and the equipment ground and the earth are also insulated, and the equipment ground can pass through one or A plurality of grounding wires are connected to the ground; the current detecting device detects the current flowing through each of the grounding wires between the ground of the device and the ground, and the currents flowing through the respective grounding wires are added together in the direction of the inflowing earth to obtain the Area to ground current
  • a more obvious example is a three-phase high-voltage cable with armor, as shown in Figure 11, where the area 5 and the area 6 are cables with a shield, the outer side of the cable metal is an insulating layer, the outside of the insulation It is a metal shielding layer.
  • the metal shielding layer of the armored cable has an armored steel strip on the outside, and the outer side of the armored steel strip is an insulating sheath; the copper wire is usually used to connect the shielding layer and the armored steel at both ends of the cable, and Grounding the copper wire; using a current detecting device to detect the current flowing through the copper wires at both ends, and adding the current at both ends to the direction of the inflowing earth, the ground current of the cable can be obtained; if the cable is used as a region The ground current is the area to ground current of the cable
  • the method of off-line measurement or on-line measurement is used to detect the area III relative to the ground contact B EA0 , B EB0 , B EC0 of the area ;
  • the measurement method "measures the area of the region three relative to the ground cells B EA0 , B EB0 , B EC0 ;
  • the relative ground conductances G EA , G EB , G EC are measured according to the aforementioned “Measurement method for the distribution of the area-to-ground parameters of the distribution network”, G EA , G EC , if measured
  • the region 3 has an abnormality in the relative conductances G EA , G EB , and G EC . For example, a relative conductance value of the region is low, and it is determined that there is a ground fault in the region.
  • the off-line or on-line measurement area three relative ground conductances G EA0 , G EB0 , G EC0 and area three are relatively grounded B EA0 , B EB0 , B EC0 ; a ground fault occurs in the distribution network Measuring the relative ground voltage of the region in the region And regional to ground current
  • the offline or online measurement area 3 is relatively electrically charged B EA0 , B EB0 , B EC0 ;
  • the area three measured before and after is compared with the ground contact B EA0 , B EB0 , B EC0 and B EA , B EB , B EC . If the difference is large, it can be determined that there is a ground fault in the range of the area.
  • Figure 5 is a schematic diagram of the basic principle of the grounding fault area location system of the distribution network.
  • the system comprises a voltage transformer PT, a zero sequence current transformer CT1 ⁇ CT5, a voltage detection module, a current detection module, a voltage offset device, a voltage offset control device and a signal processing device; wherein the zero sequence current transformer divides the line For 5 regions, CT1, CT2, and CT4 detect the region-to-ground current of region 1, CT2 and CT3 detect the region-to-ground current for region 2, CT3 separately detects the region-to-ground current for region 3, and CT4 and CT5 detect region 4 for region.
  • CT5 separately detects the area-to-ground current of region 5; the zero-sequence current transformer and current detection module form a current detecting device, and the current detecting device detects and detects the zero-sequence current of each zero-sequence current transformer, and zero-sequence current The detection result is sent to the signal processing device.
  • the voltage detecting device is composed of a voltage transformer and a voltage detecting module, and the voltage monitoring device detects the relative ground voltage of the region three And sending the detection result to the signal processing device;
  • three capacitors C1, C2, C3 and three single-phase contactors J1, J2, J3 for controlling three capacitors C1, C2, C3 are voltage-shifting devices; the voltage offset control device receives signals from the signal processing device. Control the action of the voltage offset device.
  • One ends of the three capacitors C1, C2, and C3 of the voltage shifting device are grounded, and the other ends of the three capacitors C1, C2, and C3 are respectively connected to the three-phase line through three single-phase contactors J1, J2, and J3.
  • the purpose of introducing the voltage offset device is to artificially cause the three relative ground voltage imbalance of the distribution network, and lead to an increase in the current to the ground in each region, so that on the one hand, a system of equations for solving the region-to-ground parameters satisfying the linearly independent need can be obtained.
  • the increase of regional-to-ground current to a certain extent is conducive to improving the accuracy of ground current measurement, and is conducive to improving the accuracy of regional-to-ground parameters.
  • the signal processing device receives the voltage from the region three from the voltage detecting device, receives each zero-sequence current from the current detecting device, and uses the zero-sequence current detecting value of the signal processing device to calculate the regional-to-ground current of each region.
  • the signal processing device detects the regional relative electrical susceptance B EA0 , B EB0 , B EC0 of each region according to the aforementioned “region-to-ground parameter measurement method for one area of the distribution network”;
  • the method of artificially changing the relative ground voltage may be to ground the distribution network one phase; it may be to ground one phase of the distribution network through a resistor, an inductor or a capacitor; it may be at a neutral point or an artificial neutral point of the distribution network.
  • Adding an offset power supply between the point or the artificial neutral point and the ground causes the neutral point of the distribution network to shift to the ground voltage; the neutral point of the transformer may be offset by adjusting the tap changer of the transformer; It is a combination of the above methods to adjust the relative ground voltage of the distribution network.
  • Figure 6 is a schematic diagram of the principle of adjusting the three relative ground voltages by using a grounding resistor
  • Three resistors R1, R2, R3 and three single-phase contactors J1, J2, J3 controlling the three resistors R1, R2, R3 are added in the distribution network.
  • One ends of the three resistors R1, R2, and R3 are grounded, and the other ends of the three resistors R1, R2, and R3 are respectively connected to the three-phase line through three single-phase contactors J1, J2, and J3.
  • the principle of using a resistor to adjust the neutral-to-ground voltage is similar to the principle of using a capacitor to adjust the neutral-to-ground voltage. It is also possible to provide only one resistor, one end of which is grounded, and the other end of the resistor is connected to the three-phase line through three single-phase contacts.
  • Fig. 7 is a schematic diagram showing the principle of adjusting three relative ground voltages by using a grounding reactor.
  • Three reactors L1, L2, L3 and three single-phase contactors J1, J2, J3 for controlling the three reactors L1, L2, L3 are added in the distribution network.
  • One ends of the three reactors L1, L2, and L3 are grounded, and the other ends of the three reactors L1, L2, and L3 are respectively connected to the three-phase lines through three single-phase contactors J1, J2, and J3.
  • the principle of using a reactor to adjust the neutral-to-ground voltage is similar to the principle of using a capacitor to adjust the neutral-to-ground voltage.
  • FIG. 8 is a schematic diagram of the principle of adjusting three relative ground voltages by using a grounding switch.
  • Three single-phase earthing switches DL1, DL2, DL3 and three fuses RD1, RD2, RD3 are added to the distribution network.
  • One ends of the three single-phase grounding switches DL1, DL2, and DL3 are grounded, and the other ends of the three single-phase grounding switches DL1, DL2, and DL3 are respectively connected to the three-phase lines through three fuses RD1, RD2, and RD3.
  • the principle of adjusting the neutral-to-ground voltage with a single-phase grounding switch is similar to the principle of adjusting the neutral-to-ground voltage with a resistor, which is equivalent to a resistance of 0 ⁇ .
  • some distribution networks are equipped with a single-phase grounding switch. When a ground fault occurs in the system, the single-phase grounding switch is used to short-circuit the fault phase to the ground, which can extinguish the arc in time. For such a system, the existing system can be utilized.
  • the single-phase earthing switch realizes the neutral point voltage adjustment of the distribution network.
  • FIG. 9 is a schematic diagram showing the principle of adjusting the neutral point to ground voltage by using a voltage regulating device connected in series between the neutral point and the ground.
  • One ends of the three reactors L1, L2, and L3 are respectively connected to a three-phase line, and the other ends of the three reactors are connected together to form an artificial neutral point.
  • the secondary coil of the transformer T1 is connected in series between the artificial neutral point and the earth; one end of the primary coil of the transformer T1 is connected to the neutral line N of the 380V low voltage system, and the other end of the primary coil can pass through three switches K1, K2, K3 respectively. Connected to the phase lines A, B, and C of the low voltage system.
  • the three fuses RD1, RD2, RD3 are set to provide short-circuit protection.
  • the three switches K1, K2 and K3 are respectively closed to adjust the neutral-to-ground voltage of the distribution network to be measured. Reasonable setting of the capacity, ratio and leakage resistance of the transformer T1 can achieve an ideal voltage regulation effect.
  • FIG. 10 is a schematic diagram of the positioning principle of the ground fault area of the distribution network provided with the ground voltage detecting device for the distribution electric room.
  • the substation is equipped with voltage transformers PT1, PT1 secondary connected to the main station voltage detection device to detect the relative ground voltage of the substation bus;
  • QF1 is an outlet switch of the substation;
  • QF2 is the incoming switch of the distribution electric room, the distribution electric room There are also two outlet switches QF3 and QF4.
  • the sub-distribution room is provided with voltage transformers PT2 and PT2 secondary sub-station voltage detecting devices to detect the relative ground voltages of the distribution electric bus bars.
  • CT1 and CT2 detect the ground current of the cable from the substation to the distribution electric room;
  • CT2, CT3 and CT5 detect the ground current in the distribution room of the distribution room;
  • CT3 and CT5 respectively Detect the ground current of the outgoing loop controlled by QF3 and QF4; the first end of the outer shield of the cable of QF3 loop is grounded through the grounding wire, the tail end is grounded by the overvoltage protector, and the grounding wire of the first end passes through the precision current transformer CT4
  • the ground current of the cable is detected by CT4; the first and last ends of the outer shield of the cable of QF4 loop are grounded through the grounding wire.
  • the grounding wire of the first end passes through the precision current transformer CT6, and the ground wire of the tail end passes through the precision current.
  • the transformer CT7 adds the currents measured by CT6 and CT7 to the direction vector flowing into the earth to obtain the current to the ground of the cable.
  • the area 1 uses the three relative ground voltages detected by the primary station voltage detecting means; the area 2, the area 3, the area 4 area 5, and the area 6 use the three relative ground voltages detected by the substation voltage detecting means.
  • a voltage detecting device can be set in the distribution electric chamber to reduce the error of the area to ground voltage in the power supply range of the distribution electric room. Improve the positioning of the ground fault area within the power supply range of the distribution electric room.
  • FIG 11 Schematic diagram of the positioning principle of the ground fault area of the ring network
  • This figure takes the partial line of the ring network power supply system powered by two substations as an example to illustrate the positioning principle of the ground fault area of the distribution network when the ring network is powered.
  • Each of the two substations has a distribution network ground fault area location system, and each of the two substations also has a set of voltage offset devices.
  • All lines are divided into 12 areas, including 3 ring network cabinet areas, 8 line areas and 1 transformer area.
  • the area-to-ground current of 12 areas is measured by 13 zero-sequence current transformers.
  • Area 1, area 4, and area 9 are ring network cabinet areas, detecting ground faults inside the ring network cabinet; area 2, area 3, area 5, area 6, area 8, area 10, area 11, and area 12 are each responsible for
  • area 7 is responsible for a transformer;
  • CT7 uses three current transformers to detect the three-phase current, and the FTU calculates the zero-sequence current.
  • it is sometimes inconvenient to install zero-sequence current transformers which can be obtained by three-phase current calculation.
  • the zero-sequence current error measured by this method is large, which may affect the accuracy of judgment.
  • Zero sequence current transformer is large, which may affect the accuracy of judgment.
  • the three-phase line-to-ground voltage of the two substations is detected by two power distribution master systems and supplied to their respective distribution networks.
  • the ground fault area localization system measures the amplitude and phase of the zero sequence current of each current detection point by the remote terminal (DTU), the feeder remote terminal (FTU) and the transformer remote terminal (TTU) of the ring network cabinet opening and closing
  • Two substation power distribution master station systems are then transmitted by two power distribution master station systems to two distribution network ground fault area location systems, and two substation power distribution master station systems respectively to their respective distribution network ground fault areas
  • the positioning system transmits the three relative ground voltages of the substation and the power supply range information and the line operation mode information of the substation, and the grounding fault area localization system of the two stations respectively conducts the ground parameter measurement for each area within the scope of the system. And regional positioning of ground faults.
  • the power supply ranges of the two substations overlap each other. For example, some of the lines and equipment within the power supply range of the A substation are temporarily powered by the B substation for some reason; at this time, the original power supply from the B substation Ground fault monitoring of lines and equipment within the power supply range of A substation is a problem to be solved; for these areas, the three relative ground voltages of this part of the line are detected by the B substation, and the ground fault area of the distribution network is transmitted to the A substation.
  • the A substation handles the ground fault detection of this part of the line and equipment; it is necessary to use the communication between the two sets of distribution network ground fault area positioning systems to realize the transmission of relevant data;
  • Both sets of systems use GPS standard time and second pulse to realize phase synchronization detection of three relative ground voltages and zero sequence currents.
  • the phase detection accuracy of three relative ground voltages and zero sequence currents can be improved, and the accuracy of ground parameter measurement can be improved and improved.
  • the accuracy of the ground fault area positioning judgment; on the other hand, the coordination between the two systems can be realized, and the area localization function of the ground fault of the power supply line of the ring network can be solved.
  • the distribution network ground fault area location system can provide the ground parameter measurement and ground fault location results to the power distribution master station system, and the power distribution master station system completes the isolation of the ground fault area.
  • the function of the distribution network ground fault area location system can also be included in the power distribution master station system.
  • FIG. 12 is a schematic diagram of application of the present invention in positioning a ground fault area of a small resistance grounding system
  • the neutral point is connected with a resistor R1 with a resistance of about several tens of ohms through the neutral point of the small resistance grounding system and the ground.
  • R1 resistor
  • the grounding fault area is also required to be grounded through a small resistance grounding system.
  • the ground fault area positioning method can be used to realize the ground fault location and isolate the fault area.
  • the three relative ground voltage adjustment method of the neutral point via the small resistance grounding system is as follows: as shown in FIG. 13, one end of the small resistance is grounded, and the other end is connected to the neutral point through the switch J4, and the switch is turned off during the detection area to the ground parameter. J4, the measurement ends the closing switch J4; once the ground fault occurs during the measurement area to the ground parameter, immediately close the switch J4, become a small resistance grounding system, quickly cut off the fault circuit; if there is a high resistance ground fault, the protection refuses, can pass this
  • the ground fault area localization method of the invention detects an area where a ground fault exists and isolates the fault loop.
  • Figure 13 is a schematic diagram of the principle of the grounding fault area localization system of the distribution network with the upper computer system
  • the distribution network ground fault area location system includes a host computer system, a voltage detection module, a current detection module, a concentrator with a GPS timing, a wireless communication module, and a voltage offset device.
  • the voltage detection module detects the relative ground voltage of the region three; the current detection module detects the zero sequence current of each detection point; the GPS concentrator provides the GPS second pulse to the voltage detection module and the current detection module to measure the phase of the voltage and current.
  • upper computer system controls voltage offset device to adjust three relatives of distribution network by voltage offset controller Ground voltage, in conjunction with the grounding fault area locating system of the distribution network, the measurement of the regional-to-ground parameters; the upper-machine system controls the work of the grounding fault area locating system of the distribution network, and detects the area of each area according to the aforementioned regional-to-ground parameter measurement method.
  • the grounding parameters when there is a ground fault in the distribution network, determine whether there is a ground fault in each area according to the above-mentioned regional ground fault judgment method, so as to realize the ground fault area location function of the distribution network.
  • the upper computer system can be used to realize communication with other distribution network ground fault area positioning systems, realize communication with the distribution automation system, and realize communication with the power dispatching system.
  • the previous examples basically adopt the parallel partitioning method, which divides the power supply and distribution lines into several areas, and there is no overlap between the areas, and the area where the ground fault exists can be directly judged.
  • the hierarchical partitioning method can also be adopted, that is, the power supply and distribution network is first divided into several large areas, and then a plurality of small areas are divided in the large area, and a plurality of smaller areas can be further divided in the small area.
  • a specific scheme of the hierarchical partitioning method is to arrange zero-sequence current transformers step by step from the substation.
  • the detection range of each zero-sequence current transformer includes all the subsequent lines; if a pre-stage zero-sequence current transformer detects grounding Fault, and none of the subsequent zero-sequence current transformers detect a ground fault, then the ground fault is in the region between the two stages.
  • FIG. 14 is a schematic diagram of a simulation test of a ground fault detection method for a distribution network area and a ground fault regionalization system for a distribution network according to the present invention
  • the ground currents of the entire range of the region 1, the region 2, the region 3, and the region 4 are detected by CT1, and the ground currents of the entire range of the region 2, the region 3, and the region 4 are detected by the CT2, and the region 3 of the region 3 is detected by the CT3.
  • the ground current of zone 4 is detected by CT5; if CT1 detects a ground fault and the CT2 test result is normal, the ground fault is in the range of zone 1. If both CT1 and CT2 detect a ground fault, the ground point is after CT2.
  • the grounding fault selection and positioning of the neutral point through the arc suppression coil grounding system is relatively difficult, so the simulation experiment is configured according to the neutral point through the arc suppression coil grounding system.
  • the present invention is also applicable to other forms of small current grounding systems;
  • the line is a 10kV neutral point arc-suppression coil grounding system.
  • four zero-sequence current transformers CT1 ⁇ CT4 respectively detect the zero-sequence current of four regions, and area 4 is for the neutral point eliminator.
  • the arc coil grounding system is set with a large capacitive current, and the simulation experiment is performed only for the area 1, the area 2, and the area 3.
  • the single-phase conductor is grounded by a grounding resistor to adjust the three relative ground voltages.
  • the following is a simulation result of the grounding parameter measurement and the ground fault area localization method for the power distribution network area of the present invention.
  • the area-to-ground parameters in the simulation experiment are shown in Table 1.
  • the arc suppression coil reactance is 0.2H; the bias voltage is used to adjust the three relative ground voltages, and the bias resistance is 1k ⁇ .
  • Table 2 shows the three relative ground voltage and area to ground current measurement data.
  • Table 2 They are the area-to-ground currents of Zone 1, Zone 2, and Zone 3, respectively.
  • the measured value of the relative capacitance of the area three is basically consistent with the actual value. Therefore, the "measurement method of the grounding parameter of the power supply and distribution network area" can be used to detect the relative capacitance of the three relative areas.
  • the area 3 has a relative capacitance; when a ground fault occurs in the power supply and distribution network, the neutral point to ground voltage is changed, and the three relative ground voltages are measured. And regional to ground current The three relative ground voltages and the area-to-ground currents are substituted into the following relationship along with the known area three capacitances:
  • the area-to-ground parameters in the simulation experiment are shown in Table 4.
  • the arc suppression coil reactance is 0.2H; the bias voltage is used to adjust the three relative ground voltages, and the bias resistance is 1k ⁇ .
  • Table 5 shows the three relative ground voltage and area to ground current measurement data.
  • Table 5 They are the area-to-ground currents of Zone 1, Zone 2, and Zone 3, respectively.
  • the measured value of the ground resistance of the "Area 1" A phase and the “Zone 3" C phase is close to 10k ⁇ , which is basically consistent with the actual value; the resistance of other ground resistance is relatively high; therefore, the method can detect the grounding.
  • the resistance of the transition resistor, and the area where the ground fault exists can be judged accordingly.
  • Simulation Experiment 3 The simulation experiment of detecting the ground resistance and the three relative ground capacitance of the ground fault phase by using the "Measurement Method 4 for Grounding Parameters of Power Supply and Distribution Network Area" of the present invention.
  • the “Measurement Method 4 for Grounding Parameters in the Power Supply and Distribution Network Area” is to determine the ground fault of the phase after the ground fault occurs in the power supply and distribution network. For example, if there is a ground fault in the C phase, the phase A and phase B can be set. Conductance to ground is 0; change the neutral point to ground voltage, measure three relative ground voltage And regional to ground current Substitute the following equation:
  • C can be calculated from the ground conductance G EC and the three relative ground conductance B EA , B EB , B EC , and can convert the C relative ground resistance R CE and the three relative ground capacitances C EA , C EB , C EC .
  • the relative ground resistance of "Zone 3" is 9.85k ⁇ , which is close to 10k ⁇ .
  • the three relative capacitances C EA , C EB and C EC are also close to the actual value, so the method can detect the ground transition resistance of the fault zone. Value and three relative capacitance values.
  • Simulation Experiment 4 The simulation experiment of detecting the ground resistance of the ground fault phase by using the "Measurement Method 5 of the Grounding Parameters of the Power Distribution Network Area" of the present invention.
  • Three relative ground capacitances are known; after a ground fault occurs in the power distribution network, it is first determined that there is a ground fault in that phase. For example, if there is a ground fault in phase C, the ground conductance of phase A and phase B can be set to 0; Three relative ground voltage And regional to ground current Substituting the three relative ground voltages and the area-to-ground currents with the known area three capacitances into the following equation:
  • C can be calculated relative to the ground conductance G EC and the C relative ground resistance R CE can be converted.
  • the area-to-ground parameters in the simulation experiment are shown in Table 8.
  • the arc suppression coil reactance is 0.2H; the bias voltage is used to adjust the three relative ground voltages, and the bias resistance is 1k ⁇ .
  • Set a ground fault in phase C of "Zone 3" and the fault resistance is 100 ⁇ .
  • Table 9 shows the three relative ground voltage and area to ground current measurement data.
  • Table 9 They are the area-to-ground currents of Zone 1, Zone 2, and Zone 3, respectively.
  • Simulation experiment 5 The simulation experiment of determining whether there is a ground fault in the region is determined by using the "fourth method for the grounding fault area of the power distribution network".
  • the “fourth method for the grounding fault area of the power distribution network” is when the ground fault does not exist in the area, the three relative grounds B EA , B EB , B EC within the measurement area; when the grounding fault occurs in the power supply and distribution network Measuring three relative ground voltages of the region And regional to ground current Determining the three relative ground sensitivities B EA , B EB , B EC measured when there is no ground fault in the area and the three relative ground voltages of the area measured when a ground fault occurs in the power supply and distribution network And regional to ground current Whether it conforms to the relationship:
  • the method for locating the grounding fault area of the power distribution network is five.
  • the three relative grounds B EA , B EB , B EC in the measuring area are in the ground fault of the power supply and distribution network.
  • the three relative grounding sensitivities B EA , B EB , and B EC are measured again in the area, and the two measurement results are compared before and after, to determine whether there is a ground fault in the area.
  • the simulation experiment method is: after the ground fault occurs, the three relative ground electric sensitivities B EA , B EB , B EC are measured in the range of “measurement method for the grounding parameter of the power supply and distribution network area”.
  • the three relative ground voltages and the area-to-ground current when a ground fault occurs will be taken as a set of measurement data.
  • the A-phase bias resistor is closed, a set of three relative ground voltages and a region-to-ground current data are measured, and two sets of data are used for calculation. .
  • the area-to-ground parameters in the simulation experiment are shown in Table 12.
  • the arc suppression coil reactance is 0.2H; the bias voltage is used to adjust the three relative ground voltages, and the bias resistance is 1k ⁇ .
  • Table 13 shows the three relative ground voltage and area to ground current measurement data.
  • Table 13 They are the area-to-ground currents of Zone 1, Zone 2, and Zone 3, respectively.
  • Table 14 compares the relative capacitance of the three regions before and after the fault.
  • the three relative ground capacitances of "Zone 3" differ greatly before and after the fault, while the three relative ground capacitances of other regions change little before and after the fault, and accordingly, it can be judged that "Zone 3" is the ground fault area.
  • the method for measuring the regional line-to-ground parameter of the present invention is not limited to searching and locating the ground fault, and can be applied to other aspects, for example, it can be used for measuring the distributed capacitance of the distribution network, and providing a basis for the adjustment of the arc-suppression coil; many
  • the sub-measurement three relative ground voltage and the area-to-ground current calculation of the area-to-ground parameters are all within the protection scope of the present invention.
  • the ground fault area localization method of the present invention is not limited to the foregoing method, and as long as it is a partial area or section of the power line, the ground fault determination, positioning or protection by the ground parameter of the line in the measurement area belongs to the present invention. protected range.
  • the distribution network area ground fault detection method and the distribution network ground fault area localization system of the present invention are not limited to the foregoing ranges, for example, the method of applying an offset voltage between a neutral point or an artificial neutral point and ground is not limited to this document.
  • the inverter power supply can be used to supply the voltage offset transformer; the switching offset load can not only use the mechanical switch, but also other switching methods such as thyristor switching. It is within the protection scope of the present invention to measure the regional-to-ground parameters and ground fault determination and positioning by artificially adjusting the neutral-to-ground voltage method.

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Abstract

针对配电网中的一个区域，在该区域不存在接地故障时，离线或在线测量该区域的区域三相对地电纳；在配电网出现接地故障时，测量区域三相对地电压和区域对地电流，利用区域三相对地电压、区域对地电流和区域三相对地电纳计算区域三相对地电导，根据计算结果判断该区域是否存在接地故障；还可以在配电网出现接地故障时，测量区域三相对地电压和区域对地电流，利用区域三相对地电压、区域对地电流和区域三相对地电纳之间的关系，通过计算，判断该区域是否存在接地故障。在配电网中划定不同的区域，在配电网出现接地故障时，利用上述方法针对每个区域进行本区域是否存在接地故障检测，确定哪个区域存在接地故障，从而实现配电网接地故障区域定位功能。

Description

一种配电网区域接地故障检测方法及一种配电网接地故障区域定位系统 技术领域
本发明涉及配电网区域接地故障检测和配电网接地故障区域定位。
背景技术
现在中压配电系统一般都采用小电流接地系统，一些有特殊要求的低压配电系统也采用小电阻接地系统。采用中性点经消弧线圈接地方式可降低配电网发生接地故障时流过接地故障点的电流，有利于配电网的连续平稳供电，但是由消弧线圈产生的补偿电流的加入，使早期普遍采用的利用零序电流的幅值和相位进行接地选线的规则失效，为此国内外相关科研人员研究开发了多种途径的接地选线和定位方法，但到目前为止，实际应用效果并不理想，尤其是对于高阻接地故障的选线和定位还没有很好的解决方案。由于小电流接地系统在接地选线定位方面存在的问题，国内有些配电网改为采用中性点经小电阻接地系统，目的是在系统出现接地故障时能够及时切除故障线路；但中性点经小电阻接地系统出现高过渡电阻接地故障时，由于故障电流小，保护可能拒动，所以也同样存在接地选线定位的难题。接地选线定位已成为配电网提高供电质量的一个瓶颈，迫切需要更准确、更有效的接地选线定位方法。
发明内容
本发明的目的是提供一种配电网区域接地故障检测方法，实现在配电网出现接地故障时，在线判断一个区域范围内是否存在接地故障。
本发明还提供一种配电网接地故障区域定位系统，该系统利用配电网区域接地故障检测方法实现配电网的接地故障区域定位功能。
为了实现上述目的，本发明的配电网区域接地故障方法如下:
在配电网中划定一个区域，所述区域中可以只包括一台设备或一段线路，也可以包括相连并相邻的若干台设备和若干段线路；
采用离线检测或在线检测的方法测量所述区域的区域三相对地电纳BEA0、BEB0、BEC0；
利用电压检测装置检测所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000001
利用电流检测装置检测流入所述区域的区域对地电流
Figure PCTCN2015074276-appb-000002
在配电网出现接地故障期间，利用所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000003
区域对地电流
Figure PCTCN2015074276-appb-000004
和区域三相对地电纳BEA0、BEB0、BEC0，判断所述区域是否存在接地故障。
针对所述区域，区域三相对地电压
Figure PCTCN2015074276-appb-000005
区域对地电流
Figure PCTCN2015074276-appb-000006
和区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间存在以下关系：
Figure PCTCN2015074276-appb-000007
在所述区域不存在接地故障期间，区域三相对地电导GEA0＝GEB0＝GEC0＝0；这时区域对地电流
Figure PCTCN2015074276-appb-000008
即是区域电容电流
Figure PCTCN2015074276-appb-000009
区域三相对地电压
Figure PCTCN2015074276-appb-000010
区域对地电流
Figure PCTCN2015074276-appb-000011
和区域三相对地电纳BEA0、BEB0、BEC0之间存在以下关系：
Figure PCTCN2015074276-appb-000012
利用这个关系式，在不同的区域三相对地电压
Figure PCTCN2015074276-appb-000013
下，测量多组区域三相对地电压
Figure PCTCN2015074276-appb-000014
和区域电容电流
Figure PCTCN2015074276-appb-000015
每组数据可形成一个求解区域三相对地电纳BEA0、BEB0、BEC0的方程，通过解方程，可以得到所述区域的区域三相对地电纳BEA0、BEB0、BEC0。
针对类似三相电缆这样的三相对地电纳BEA0、BEB0、BEC0对称性比较好的设备，三相对地电纳相等，即BEA0＝BEB0＝BEC0，这时区域三相对地电压
Figure PCTCN2015074276-appb-000016
区域对地电容电流
Figure PCTCN2015074276-appb-000017
和区域三相对地电纳BEA0、BEB0、BEC0之间的关系式：
Figure PCTCN2015074276-appb-000018
就变为：
Figure PCTCN2015074276-appb-000019
由于
Figure PCTCN2015074276-appb-000020
所以该关系式又可以变为：
Figure PCTCN2015074276-appb-000021
可以利用后两个关系式在线测量区域三相对地电纳BEA0、BEB0、BEC0。
在配电网出现接地故障期间，如果所述区域不存在接地故障，所述区域的区域对地电流
Figure PCTCN2015074276-appb-000022
等于所述区域的区域对地电容电流
Figure PCTCN2015074276-appb-000023
如果所述区域存在接地故障，这时区域对地电流
Figure PCTCN2015074276-appb-000024
将由区域对地电容电流
Figure PCTCN2015074276-appb-000025
和经过接地故障点流入大地的接地故障电流组成；由于接地故障电流的加入，所述区域的区域对地电流
Figure PCTCN2015074276-appb-000026
与所述区域的区域对地电容电流
Figure PCTCN2015074276-appb-000027
不再相等；可据此判断所述区域是否存在接地故障。
在配电网出现接地故障期间，实时检测的区域三相对地电压
Figure PCTCN2015074276-appb-000028
和区域对地电流
Figure PCTCN2015074276-appb-000029
利用区域三相对地电压
Figure PCTCN2015074276-appb-000030
和区域三相对地电纳BEA0、BEB0、BEC0计算所述区域的区域电容电流理论值
Figure PCTCN2015074276-appb-000031
Figure PCTCN2015074276-appb-000032
将计算的区域电容电流的理论值
Figure PCTCN2015074276-appb-000033
与实际测量的区域对地电流
Figure PCTCN2015074276-appb-000034
相比较，如果区域电容电流的理论值
Figure PCTCN2015074276-appb-000035
与区域对地电流
Figure PCTCN2015074276-appb-000036
接近，则本区域范围内不存在接地故障；如果区域电容电流的理论值
Figure PCTCN2015074276-appb-000037
与区域对地电流
Figure PCTCN2015074276-appb-000038
之间相差较大，则本区域范围内存在接地故障。
在配电网出现接地故障时，假设所述区域不存在接地故障，区域三相对地电导GEA＝GEB＝GEC＝0，这时区域三相对地电压
Figure PCTCN2015074276-appb-000039
区域对地电流
Figure PCTCN2015074276-appb-000040
和区域三相对地电纳BEA、BEB、BEC之间的存在以下关系：
Figure PCTCN2015074276-appb-000041
利用这个关系式，在不同的区域三相对地电压
Figure PCTCN2015074276-appb-000042
下，测量多组区域三相对地电压
Figure PCTCN2015074276-appb-000043
和对应的区域对地电流
Figure PCTCN2015074276-appb-000044
的数据，每组数据可形成一个求解区域三相对地电纳BEA、BEB、BEC的方程，通过解方程，可以求解出所述区域的区域三相对地电纳BEA、BEB、BEC；如果所述区域范围内不存在接地故障，所述区域的区域对地电流
Figure PCTCN2015074276-appb-000045
等于所述区域的区域对地电容电流
Figure PCTCN2015074276-appb-000046
检测的区域三相对地电纳BEA、BEB、BEC与之前测量的区域三相对地电纳BEA0、BEB0、BEC0应该接近；如果所述区域范围内存在接地故障，由于故障电流的 加入，所述区域的区域对地电流
Figure PCTCN2015074276-appb-000047
与所述区域的区域对地电容电流
Figure PCTCN2015074276-appb-000048
不再相等，检测的区域三相对地电纳BEA、BEB、BEC与之前测量的区域三相对地电纳BEA0、BEB0、BEC0之间应该存在较大的差异；可据此判断所述区域是否存在接地故障。
在配电网出现接地故障期间，如果所述区域不存在接地故障，所述区域的区域对地电流
Figure PCTCN2015074276-appb-000049
等于所述区域的区域对地电容电流
Figure PCTCN2015074276-appb-000050
如果所述区域存在接地故障，这时区域对地电流
Figure PCTCN2015074276-appb-000051
将由区域对地电容电流
Figure PCTCN2015074276-appb-000052
和由接地故障点流入大地的故障电流组成；这时，可利用区域三相对地电压
Figure PCTCN2015074276-appb-000053
区域对地电流
Figure PCTCN2015074276-appb-000054
和区域三相对地电纳BEA、BEB、BEC和区域三相对地电导GEA、GEB、GEC之间的关系，在线测量区域三相对地电导GEA、GEB、GEC，根据测量结果判断所述区域是否存在接地故障。
在配电网出现接地故障期间，所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000055
区域对地电流
Figure PCTCN2015074276-appb-000056
和区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间存在以下关系：
Figure PCTCN2015074276-appb-000057
将区域三相对地电纳BEA0、BEB0、BEC0作为已知值代入，可得到求解区域三相对地电导GEA、GEB、GEC的方程式：
Figure PCTCN2015074276-appb-000058
将已知的区域三相对地电纳BEA0、BEB0、BEC0代入，得到下述关系式：
Figure PCTCN2015074276-appb-000059
利用这个关系式，在不同的区域三相对地电压
Figure PCTCN2015074276-appb-000060
下，测量多组区域三相对地电压
Figure PCTCN2015074276-appb-000061
区域对地电流
Figure PCTCN2015074276-appb-000062
的数据，每组数据可形成一个求解区域三相对地电导GEA、GEB、GEC的方程，通过解方程，可以求解出所述区域的区域三相对地电导GEA、GEB、GEC；如果区域三相对地电导GEA、GEB、GEC中出现较大值，或者区域三相对地电导GEA、GEB、GEC之间不平衡率较大，可判定该区域存在接地故障。
在配电网出现接地故障时，首先判断哪一相存在接地故障；
假设已经确定配电网的C相出现接地故障，可设定所述区域的A相和B相的区域对地电导GEA、GEB为0，即GEA＝GEB＝0；前述的区域三相对地电压
Figure PCTCN2015074276-appb-000063
和区域对地电流
Figure PCTCN2015074276-appb-000064
与区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间的关系：
Figure PCTCN2015074276-appb-000065
变为求解C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC关系式：
Figure PCTCN2015074276-appb-000066
利用这个关系式，在不同的区域三相对地电压
Figure PCTCN2015074276-appb-000067
下，测量多组区域三相对地电压
Figure PCTCN2015074276-appb-000068
区域对地电流
Figure PCTCN2015074276-appb-000069
的数据，每组数据可形成一个求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的方程，通过解方程，可以求解出所述区域的区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC；如果区域C相对地电导GEC数值较大，可判定该区域存在接地故障。
在配电网出现接地故障时，首先判断哪一相存在接地故障；
假设已经确定配电网的C相出现接地故障，可设定所述区域的A相和B相的区域对地电导GEA、GEB为0，即GEA＝GEB＝0；前述的三相对地电压
Figure PCTCN2015074276-appb-000070
和区域对地电流
Figure PCTCN2015074276-appb-000071
与区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间的关系：
Figure PCTCN2015074276-appb-000072
变为求解区域C相对地电导GEC的关系式：
Figure PCTCN2015074276-appb-000073
将已知的区域三相对地电纳BEA0、BEB0、BEC0代入，得到下述关系式：
Figure PCTCN2015074276-appb-000074
在同一时刻检测三相对地电压
Figure PCTCN2015074276-appb-000075
和区域对地电流
Figure PCTCN2015074276-appb-000076
将检测的结果代入上述关系式可形成求解区域C相对地电导GEC的方程，可计算出区域C相对地电导GEC；如果区域C相对地电导GEC数值较大，可判定该区域存在接地故障。
针对所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000077
的测量方法是：可以在区域内测量所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000078
也可以在所述区域外测量与所述区域内三相线路存在电连接关系的三相导体的三相对地电压
Figure PCTCN2015074276-appb-000079
利用区域外的测量结果计算区域内的区域三相对地电压
Figure PCTCN2015074276-appb-000080
还可以将区域外的测量结果直接作为区域内的区域三相对地电压
Figure PCTCN2015074276-appb-000081
加以利用。
针对所述区域的区域对地电流的检测方法是：在所述区域与其他区域交界处安装电流检测装置，利用电流检测装置检测从其他区域流入所述区域的零序电流，将全部流入所述区域的零序电流按零序电流流入所述区域的方向矢量相加，可得到所述区域的区域对地电流
Figure PCTCN2015074276-appb-000083
针对所述区域的区域对地电流
Figure PCTCN2015074276-appb-000084
的检测方法是：在所述区域范围内，各相导体与大地之间存在一个设备地，设备地与各相导体之间处于绝缘状态，设备地与大地之间也处于绝缘状态，设备地可通过一条或多条接地线与大地连接；利用电流检测装置检测流过设备地与大地之间的各条接地线的电流，将流过各条接地线的电流按流入大地的方向矢量相加，可得到所述区域的区域对地电流
Figure PCTCN2015074276-appb-000085
可以采用人为调整配电网的三相对地电压
Figure PCTCN2015074276-appb-000086
的方法配合区域三相对地参数的检测，每改变一次三相对地电压
Figure PCTCN2015074276-appb-000087
测量一次所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000088
和区域对地电流
Figure PCTCN2015074276-appb-000089
形成求解所述区域的区域三相对地参数的线性不相关的方程组，通过解方程，可以获得所述区域的区域三相对地参数，从而实现可以随时进行区域三相对地参数的检测，并且提高检测精度的目的。
人为调整配电网三相对地电压的方法可以是使配电网一相接地；可以是使配电网一相通过电阻、电感或电容接地；可以是在配电网中性点或人工中性点与地之间加入电阻、电感或电容；可以是使连接在配电网中性点或人工中性点与地之间的电阻、电感或电容的阻抗发生改变；可以是通过在配电网中性点或人工中性点与地之间加入偏移电源使配电网中性点对地电压发生偏移；可以是通过调整变压器的分接开关使变压器的输出电压发生中性点偏移；可以是采用上述方法的组合调整配电网三相对地电压。
本发明的配电网接地故障区域定位系统如下：
所述配电网接地故障区域定位系统在配电网中划分不同的区域，按照前述的配电网区域接地故障检测方法中的一种方法或几种方法，分别针对每个区域检测本区域范围内是否存在接地故障，确定接地故障在哪个区域，或确定接地故障在所检测的这些区域之外，从而实现配电网接地故障区域定位功能。
所述配电网接地故障区域定位系统包括电压检测装置、电流检测装置、电压偏移装置和配电网接地故障区域定位装置；利用分布安装的电流检测装置在配电网中划定不同的区域；由电压检测装置检测各区域的区域三相对地电压
Figure PCTCN2015074276-appb-000090
由电流检测装置检测各电流检测点的电流；由配电网接地故障区域定位装置接收来自电压检测装置和电流检测装置的检测数据，经过处理得到各区域的区域三相对地电压
Figure PCTCN2015074276-appb-000091
和各区域的区域对地电流
Figure PCTCN2015074276-appb-000092
电压偏移装置可根据配电网接地故障区域定位装置的指令调整配电网的三相对地电压；所述配电网接地故障区域定位系统按照前述的配电网区域接地故障检测方法中的一种方法或几种方法，分别针对每个区域检测本区域范围内是否存在接地故障，从而实现配电网接地故障区域定位功能。
所述电压偏移装置可以是能够使配电网一相接地的装置；可以是能够使配电网的一相通过电阻器、电抗器或电容器接地的装置；可以是能够使电阻器、电抗器或电容器串接在供配电网络的中性点或人工中性点与地之间的装置；可以是能够使串接在供配电网络的中性点或人工中性点与地之间的电阻器、电抗器或电容器的阻抗发生改变的装置；可以是连接于配电网的中性点或人工中性点与地之间调压设备，该设备能够使供配电网络中性点对地电压发生偏移；可以是一台能够输出三相对称电压并且可以调整三相对地电压的三相电源；也可以是上述装置的组合。
所述的电压偏移装置还包括控制所述电压偏移装置的电压偏移控制装置，所述电压偏移控制装置能够根据配电网接地故障区域定位装置的指令控制所述电压偏移装置改变配电网的三相对地电压
Figure PCTCN2015074276-appb-000093
配合配电网接地故障区域定位系统实现配电网接地故障区域定位功能。
所述的配电网接地故障区域定位系统还包括信号输出装置，可由信号输出装置将区域对地参数传送给配电网中的开关装置；或由信号输出装置将区域对地参数传送给供配电自动化系统；或由信号输出装置将区域对地参数传送给上位机系统；或由信号输出装置将接地故障所在区域信息传送给供配电网络中的开关装置，由开关装置隔离存在接地故障的区域；或由信号输出装置将接地故障所在区域信息传送给供配电自动化系统，由供配电自动化系统隔离存在接地故障的区域；或由信号输出装置将接地故障所在区域信息传送到上位机系统，由供配电网络的运行人员安排相关设备的操作，隔离存在接地故障的区域。
所述的配电网接地故障区域定位系统还包括信号输入装置，所述信号输入装置可以接收来自上位机系统的信息；或接收来自配电自动化系统的信息；或接收来自开关装置的信息；所述的配电网接地故障区域定位系统可以根据接收的信息调整相关数据，或根据接收的信息调整内部的工作状态，或根据接受的信息进行相关的操作。
本发明的有益效果
1、本系统可在线测量配电网的区域对地参数，可用于在线测量配电网的电容电流，为消弧线圈调整档位提供依据；可用于查找存在三相对地参数不平衡的区域，指导系统三相电压不平衡治理；可用于小电流接地选线；可用于接地故障区域定位；测量的对地参数还可用于配电网继电保护的定值计算和接地故障点定位计算。
2、以测量区域对地参数为基础进行接地故障区域定位的方法，参加计算的是所述区域的三相对地电压、区域对地电流和区域对地参数，与系统采用哪种中性点接地方式没有关系。所以本发明不仅适用于各种小电流接地系统，而且对中性点经小电阻接地系统也同样有效；对于中性点经小电阻接地系统，如果采用适当的方法调整中性点对地电压，也可以实现区域对地参数测量和接地故障区域定位，尤其是在高阻接地故障的选线和定位方面具有优势。
3、对于多点接地故障，本发明的接地故障区域定位方法同样适用。存在接地故障的区域都会存在区域对地电流的异常变化，由于对每个区域分别进行接地故障判断，自然可以发现全部存在接地故障的区域。
4、发生高阻接地时，中性点电压偏移小，故障电流小，区域三相线路对地参数不平衡对区域对地电流的幅值和相位的影响增大；本发明的接地故障的区域定位方法考虑了三相线路对地参数的影响，可提高高阻接地故障的区域定位准确性。提高三相对地电压和区域对地电流的检测精度，有利于提高高阻接地故障区域的定位的成功率。
5、在配电网发生弧光接地期间，由于系统存在大量的谐波，会对本发明的接地故障区域定位方法产生不利影响，应设法熄灭电弧。如果在电压、电流检测环节采取滤波措施可改善接地故障判断效果。针对弧光接地选线定位问题，目前有些其他技术方案可达到良好的效果，可考虑同时采用多种接地选线定位技术进行综合判断，以期达到更好的效果。
6、系统具有自检功能。由于是以检测三相对地电压和区域对地电流为基础进行计算和判断，如果电压互感器和零序电流互感器的接线存在错误或相关设备出现故障，可在计算过程中发现。
7、由于采用工频数据进行接地故障区域定位，有利于与现有的继电保护系统结合；如果配电网配备了供配电自动化设备，可利用供配电自动化设备完成零序电流、对地电流的采集和上传，在配电主站系统中进行接地故障的区域定位，再利用供配电自动化设备实现接地故障区域的自动隔离。
附图说明
图1配电网区域集中参数等效模型
图2配电网区域集中对地参数简化模型之一
图3配电网区域集中对地参数简化模型之二
图4配电网区域接地故障判断方法的基本原理示意图
图5配电网接地故障区域定位系统基本原理示意图。
图6利用接地电阻器调整三相对地电压原理示意图
图7利用接地电抗器调整三相对地电压原理示意图
图8利用接地开关调整三相对地电压原理示意图
图9利用串接于中性点与地之间的调压设备调整中性点对地电压原理示意图
图10针对分配电室设有对地电压检测装置的配电网接地故障区域定位原理示意图
图11环网线路接地故障区域定位原理示意图
图12小电阻接地系统接地故障区域定位方面的应用原理图
图13是具有上位机系统的配电网接地故障区域定位系统原理示意图
图14配电网区域接地故障检测方法和配电网接地故障区域定位的仿真试验原理图
图1是配电网区域集中参数等效模型。
图中，RA、RB、RC是三相线路的电阻，LA、LB、LC是三相线路的自感，LAB、LAC、LBC是三相线路的互感，CAB、CAC、CBC是三相线路线间电容，REA、REB、REC是三相线路对地电阻，CEA、CEB、CEC是三相线路对地电容。
三相电流流过区域内线路，会在各相线路上产生压降，使区域范围内各相线路沿线各点对地电压不相等；假设区域范围不是很大，线路不是很长，负载电流通过线路造成的线路压降很小，可近似认为在区域范围内各相线路沿线各点对地电压相等，这样就可忽略三相线路电阻RA、RB、RC、三相线路自感LA、LB、LC、三相线路互感LAB、LAC、LBC、三相线路线间电容CAB、CAC、CBC的影响；因此，在计算区域对地参数时可只考虑三相对地电阻REA、REB、REC和对地电容CEA、CEB、CEC。
图2是配电网区域集中对地参数简化模型之一。
图中，各相导体对地参数仅有三相对地电阻REA、REB、REC和对地电容CEA、CEB、CEC。
图3是配电网区域集中对地参数简化模型之二。
由于是并联电路，为了方便计算，采用三相对地电导GEA、GEB、GEC和三相对地电纳BEA、BEB、BEC代替三相对地电阻REA、REB、REC和对地电容CEA、CEB、CEC。
图4是配电网区域接地故障判断方法的基本原理示意图。
一、针对配电网一个区域的区域接地故障判断方法基本原理图
如图4所示，在配电网中划定一个待检测区域，区域对地参数包括区域三相对地电导GEA、GEB、GEC和区域三相对地电纳BEA、BEB、BEC；
针对待检测区域，判断区域内是否存在接地故障需要配置的基本设备包括电压互感器PT、零序电流互感器CT1和CT2、电压检测模块、电流检测模块和信号处理装置；
电压检测模块与电压互感器PT的二次连接组成电压监测装置，检测区域三相对地电压
Figure PCTCN2015074276-appb-000094
电流检测模块与零序电流互感器连接组成电流检测装置，检测流过两个零序电流互感器CT1、CT2的零序电流
Figure PCTCN2015074276-appb-000095
和
Figure PCTCN2015074276-appb-000096
由信号处理装置接收来自电压检测装置检测的区域三相对地电压
Figure PCTCN2015074276-appb-000097
和来自 电流检测装置检测的零序电流
Figure PCTCN2015074276-appb-000098
和
Figure PCTCN2015074276-appb-000099
信号处理装置将零序电流
Figure PCTCN2015074276-appb-000100
和
Figure PCTCN2015074276-appb-000101
按电流流向区域内部的方向矢量相加，得到待检测区域的区域对地电流
Figure PCTCN2015074276-appb-000102
信号处理装置通过对区域三相对地电压
Figure PCTCN2015074276-appb-000103
和区域对地电流
Figure PCTCN2015074276-appb-000104
进行处理和计算，实现对所述区域范围内是否存在接地故障的判断。
二、针对配电网一个区域的区域对地参数测量方法的集中说明：
1、配电网一个区域对地参数测量方法一：
针对待检测区域，区域三相对地电压
Figure PCTCN2015074276-appb-000105
和区域对地电流
Figure PCTCN2015074276-appb-000106
与区域三相对地电导GEA、GEB、GEC和区域三相对地电纳BEA、BEB、BEC之间存在以下关系：
Figure PCTCN2015074276-appb-000107
以此关系为基础，将在同一时刻检测的区域三相对地电压
Figure PCTCN2015074276-appb-000108
和区域对地电流
Figure PCTCN2015074276-appb-000109
作为已知量，区域三相对地电导GEA、GEB、GEC和区域三相对地电纳BEA、BEB、BEC作为未知量，可以形成求解区域三相对地电导GEA、GEB、GEC和区域三相对地电纳BEA、BEB、BEC的方程；
或以此关系为基础，在已知部分区域对地参数时，将在同一时刻检测的区域三相对地电压
Figure PCTCN2015074276-appb-000110
和区域对地电流
Figure PCTCN2015074276-appb-000111
作为已知量，并且将已知的区域对地参数带入上述关系式，可形成求解未知区域对地参数的方程；
由于区域三相对地电压
Figure PCTCN2015074276-appb-000112
不是恒定不变的，在不同时刻测量区域三相对地电压
Figure PCTCN2015074276-appb-000113
和区域对地电流
Figure PCTCN2015074276-appb-000114
使我们有机会获得求解未知的区域对地参数的满足线性无关需要的方程组，通过对方程组求解，可计算出未知的区域对地参数。
通过人为改变配电网中性点对地电压，可以改变区域三相对地电压
Figure PCTCN2015074276-appb-000115
每改变一次区域三相对地电压
Figure PCTCN2015074276-appb-000116
测量一次区域三相对地电压
Figure PCTCN2015074276-appb-000117
和区域对地电流
Figure PCTCN2015074276-appb-000118
可以形成求解未知的区域对地参数的方程；重复这一过程，可获得求解未知的区域对地参数的满足线性无关需要的方程组；通过对方程组求解，可计算出未知的区域对地参数。
可将求解区域三相对地参数的矢量方程：
Figure PCTCN2015074276-appb-000119
沿A相对地电压的方向和垂直于A相对地电压的方向分解为下面的两个标量方程：
UAE·GEA+UBE·cosθB·GEB+UCE·cosθC·GEC+UBE·sinθB·BEB+UCE·sinθC·BEC
＝IE·cosθE
UBE·sinθB·GEB+UCE·sinθC·GEC-UAE·BEA-UBE·cosθB·BEB-UCE·cosθC·BEC
＝IE·sinθE
其中θB、θC、θE分别为B相对地电压
Figure PCTCN2015074276-appb-000120
C相对地电压
Figure PCTCN2015074276-appb-000121
和区域对地电流
Figure PCTCN2015074276-appb-000122
滞后A相对地电压
Figure PCTCN2015074276-appb-000123
的角度。可利用这两个标量方程进行区域对地参数的计算。
2、配电网一个区域对地参数测量方法二：
针对所述区域，在所述区域不存在接地故障时，通常区域对地阻性电流远小于区域对地容性电流，可以忽略阻性电流，设定区域三相对地电导GEA0、GEB0、GEC0均为0，则前述的 区域三相对地电压
Figure PCTCN2015074276-appb-000124
和区域对地电流
Figure PCTCN2015074276-appb-000125
与区域三相对地电导GEA、GEB、GEC和区域三相对地电纳BEA、BEB、BEC之间的关系：
Figure PCTCN2015074276-appb-000126
变为求解区域三相对地电纳BEA、BEB、BEC的关系式：
Figure PCTCN2015074276-appb-000127
在同一时刻检测区域三相对地电压
Figure PCTCN2015074276-appb-000128
和区域对地电流
Figure PCTCN2015074276-appb-000129
将检测的结果代入上述关系式可形成求解区域三相对地电纳BEA、BEB、BEC的方程；
由于区域三相对地电压
Figure PCTCN2015074276-appb-000130
不是恒定不变的，在不同时刻测量区域三相对地电压
Figure PCTCN2015074276-appb-000131
和区域对地电流
Figure PCTCN2015074276-appb-000132
使我们有机会获得求解区域三相对地电纳BEA、BEB、BEC的满足线性无关需要的方程组，通过对方程组求解，可计算出区域三相对地电纳BEA、BEB、BEC的值。
通过人为改变配电网中性点对地电压，可以改变区域三相对地电压
Figure PCTCN2015074276-appb-000133
每改变一次区域三相对地电压
Figure PCTCN2015074276-appb-000134
测量一次区域三相对地电压
Figure PCTCN2015074276-appb-000135
和区域对地电流
Figure PCTCN2015074276-appb-000136
可以形成一个求解区域三相对地电纳BEA、BEB、BEC的方程；重复这一过程，可获得求解区域三相对地电纳BEA、BEB、BEC的满足线性无关需要的方程组；通过对方程组求解，可计算出区域范围内区域三相对地电纳BEA、BEB、BEC。
可将求解区域三相对地电纳BEA、BEB、BEC的矢量方程：
Figure PCTCN2015074276-appb-000137
沿A相对地电压的方向和垂直于A相对地电压的方向分解为两个标量方程：
UBE·sinθB·BEB+UCE·sinθC·BEC＝IE·cosθE
-UAE·BEA-UBE·cosθB·BEB-UCE·cosθC·BEC＝IE·sinθE
其中θB、θC、θE分别为B相对地电压
Figure PCTCN2015074276-appb-000138
C相对地电压
Figure PCTCN2015074276-appb-000139
和区域对地电流
Figure PCTCN2015074276-appb-000140
滞后A相对地电压
Figure PCTCN2015074276-appb-000141
的角度。可利用这两个标量方程进行区域三相对地电纳BEA、BEB、BEC的计算。
在所述区域不存在接地故障时，利用该方法测量的区域三相对地电纳BEA、BEB、BEC可保存为该区域的区域三相对地电纳的参数值BEA0、BEB0、BEC0，该参数值可在区域接地故障检测中作为线路参数参加引用。在配电网出现接地故障时，可利用该方法测量区域三相对地电纳BEA、BEB、BEC，将测量结果与BEA0、BEB0、BEC0比较，用作判断本区域内是否存在接地故障的判据。
3、配电网一个区域对地参数测量方法三：
在所述区域范围内不存在接地故障时，离线或在线测量区域三相对地电纳BEA0、BEB0、BEC0；则前述的区域三相对地电压
Figure PCTCN2015074276-appb-000142
和区域对地电流
Figure PCTCN2015074276-appb-000143
与区域对地参数之间的关系：
Figure PCTCN2015074276-appb-000144
变为求解区域三相对地电导的关系式：
Figure PCTCN2015074276-appb-000145
在同一时刻检测区域三相对地电压
Figure PCTCN2015074276-appb-000146
和区域对地电流
Figure PCTCN2015074276-appb-000147
将检测的结果代 入上述关系式可形成求解区域三相对地电导GEA、GEB、GEC的方程；
由于区域三相对地电压
Figure PCTCN2015074276-appb-000148
不是恒定不变的，在不同时刻测量区域三相对地电压
Figure PCTCN2015074276-appb-000149
和区域对地电流
Figure PCTCN2015074276-appb-000150
使我们有机会获得求解区域三相对地电导GEA、GEB、GEC的满足线性无关需要的方程组，通过对方程组求解，可计算出区域三相对地电导GEA、GEB、GEC的值。
通过人为改变配电网中性点对地电压，可以改变区域三相对地电压
Figure PCTCN2015074276-appb-000151
每改变一次区域三相对地电压
Figure PCTCN2015074276-appb-000152
测量一次区域三相对地电压
Figure PCTCN2015074276-appb-000153
和区域对地电流
Figure PCTCN2015074276-appb-000154
可以形成一个求解区域三相对地电导GEA、GEB、GEC的方程；重复这一过程，可获得求解的满足线性无关需要的方程组；通过对方程组求解，可计算出区域三相对地电导GEA、GEB、GEC。
可将求解区域三相对地电导GEA、GEB、GEC的矢量方程：
Figure PCTCN2015074276-appb-000155
沿A相对地电压的方向和垂直于A相对地电压的方向分解为两个标量方程：
UAE·GEA+UBE·cosθB·GEB+UCE·cosθC·GEC
＝IE·cosθE-UBE·sinθB·BEB0-UCE·sinθC·BEC0
UBE·sinθB·GEB+UCE·sinθC·GEC
＝IE·sinθE+UAE·BEA0+UBE·cosθB·BEB0+UCE·cosθC·BEC0
其中θB、θC、θE分别为B相对地电压
Figure PCTCN2015074276-appb-000156
C相对地电压
Figure PCTCN2015074276-appb-000157
和区域对地电流
Figure PCTCN2015074276-appb-000158
滞后A相对地电压
Figure PCTCN2015074276-appb-000159
的角度。可利用这两个标量方程进行区域三相对地电导GEA、GEB、GEC的计算。
计算得到的区域三相对地电导GEA、GEB、GEC可用于判断本区域范围内是否存在接地故障的判据。
4、配电网一个区域对地参数测量方法四：
在配电网出现接地故障时，首先判断哪一相存在接地故障；
假设已经确定配电网的C相出现接地故障，可设定A相和B相的区域对地电导GEA0、GEB0为0，前述的区域三相对地电压
Figure PCTCN2015074276-appb-000160
和区域对地电流
Figure PCTCN2015074276-appb-000161
与区域对地参数之间的关系：
Figure PCTCN2015074276-appb-000162
变为求解C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC关系式：
Figure PCTCN2015074276-appb-000163
在同一时刻检测区域三相对地电压
Figure PCTCN2015074276-appb-000164
和区域对地电流
Figure PCTCN2015074276-appb-000165
将检测的结果代入上述关系式可形成求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的方程；
由于区域三相对地电压
Figure PCTCN2015074276-appb-000166
不是恒定不变的，在不同时刻测量区域三相对地电压
Figure PCTCN2015074276-appb-000167
和区域对地电流
Figure PCTCN2015074276-appb-000168
使我们有机会获得求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的满足线性无关需要的方程组，通过对方程组求解，可计算出区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的值。
通过人为改变配电网中性点对地电压，可以改变区域三相对地电压
Figure PCTCN2015074276-appb-000169
每 改变一次区域三相对地电压
Figure PCTCN2015074276-appb-000170
测量一次区域三相对地电压
Figure PCTCN2015074276-appb-000171
和区域对地电流
Figure PCTCN2015074276-appb-000172
可以形成一个求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的方程；重复这一过程，可获得求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的满足线性无关需要的方程组；通过对方程组求解，可计算出区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC。
可将求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的矢量方程：
Figure PCTCN2015074276-appb-000173
沿A相对地电压的方向和垂直于A相对地电压的方向分解为两个标量方程：
UCE·cosθC·GEC+UBE·sinθB·BEB+UCE·sinθC·BEC＝IE·cosθE
UCE·sinθC·GEC-UAE·BEA-UBE·cosθB·BEB-UCE·cosθC·BEC＝IE·sinθE
其中θB、θC、θE分别为B相对地电压
Figure PCTCN2015074276-appb-000174
C相对地电压
Figure PCTCN2015074276-appb-000175
和区域对地电流
Figure PCTCN2015074276-appb-000176
滞后A相对地电压
Figure PCTCN2015074276-appb-000177
的角度。可利用这两个标量方程进行区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的计算。
计算得到的区域C相对地电导GEC可用于本区域是否存在接地故障的判据。也可利用该方法测量本区域的区域三相对地电纳的参数值BEA0、BEB0、BEC0。
5、配电网一个区域对地参数测量方法五：
在所述区域范围内不存在接地故障时，离线或在线测量区域三相对地电纳BEA0、BEB0、BEC0；在配电网出现接地故障时，首先判断哪一相存在接地故障；
假设已经确定配电网的C相出现接地故障，可设定A相和B相的区域对地电导GEA0、GEB0为0，前述的区域三相对地电压
Figure PCTCN2015074276-appb-000178
和区域对地电流
Figure PCTCN2015074276-appb-000179
与区域对地参数之间的关系：
Figure PCTCN2015074276-appb-000180
变为求解区域C相对地电导GEC的关系式：
Figure PCTCN2015074276-appb-000181
在同一时刻检测区域三相对地电压
Figure PCTCN2015074276-appb-000182
和区域对地电流
Figure PCTCN2015074276-appb-000183
将检测的结果代入上述关系式可形成求解区域C相对地电导GEC的方程，可计算出区域C相对地电导GEC。
可将求解区域C相对地电导GEC的矢量方程：
Figure PCTCN2015074276-appb-000184
沿A相对地电压的方向和垂直于A相对地电压的方向分解为两个标量方程：
UCE·cosθC·GEC＝IE·cosθE-UBE·sinθB·BEB0-UCE·sinθC·BEC0
UCE·sinθC·GEC＝IE·sinθE+UAE·BEA0+UBE·cosθB·BEB0+UCE·cosθC·BEC0
其中θB、θC、θE分别为B相对地电压
Figure PCTCN2015074276-appb-000185
C相对地电压
Figure PCTCN2015074276-appb-000186
和区域对地电流
Figure PCTCN2015074276-appb-000187
滞后A相对地电压
Figure PCTCN2015074276-appb-000188
的角度。可利用这两个标量方程进行区域C相对地电导GEC的计算。
计算得到的区域C相对地电导GEC可用于本区域是否存在接地故障的判据。
三、配电网中一个区域的区域三相对地电压测量方法：
针对一个区域的区域三相对地电压
Figure PCTCN2015074276-appb-000189
的测量方法是：可以在区域内测量三 相对地电压
Figure PCTCN2015074276-appb-000190
也可以在区域外测量与区域内三相线路存在电连接关系的三相导体的三相对地电压
Figure PCTCN2015074276-appb-000191
利用区域外的测量结果计算区域内的三相对地电压
Figure PCTCN2015074276-appb-000192
或将区域外的测量结果直接作为区域内的三相对地电压
Figure PCTCN2015074276-appb-000193
加以利用。
四、配电网一个区域的区域对地电流的测量方法：
1、将零序电流互感器安装在本区域与其他区域交界处，检测各个零序电流互感器流入所述区域的零序电流，将各个零序电流互感器检测的零序电流按流入所述区域的方向矢量相加，可得到所述区域的区域对地电流
Figure PCTCN2015074276-appb-000194
图4所示的“配电网区域接地故障判断方法的基本原理示意图”清楚显示了利用零序电流互感器检测区域对地电流
Figure PCTCN2015074276-appb-000195
的原理。
2、在所述区域范围内，各相导体与大地之间存在一个设备地，设备地与各相导体之间处于绝缘状态，设备地与大地之间也处于绝缘状态，设备地可通过一条或多条接地线与大地连接；利用电流检测装置检测流过设备地与大地之间的各条接地线的电流，将流过各条接地线的电流按流入大地的方向矢量相加，可得到所述区域的区域对地电流
Figure PCTCN2015074276-appb-000196
比较明显的例子是带有铠装的三相高压电缆，如图11所示，图中的区域5和区域6是带有屏蔽层的电缆，电缆金属导线的外面是绝缘层，绝缘层的外面是金属屏蔽层，铠装电缆的金属屏蔽层的外面还有铠装钢带，铠装钢带的外面是绝缘护套；通常会在电缆两端利用铜导线连接屏蔽层和铠装钢，并将铜导线接地；利用电流检测装置检测流过两端铜导线的电流，将两端电流按流入大地的方向矢量相加，可以得到该条电缆的对地电流；如果将该条电缆作为一个区域，该对地电流就是该条电缆的区域对地电流
Figure PCTCN2015074276-appb-000197
五、针对配电网中一个区域的接地故障判断方法的集中说明：
在配电网中划定一个区域；
在所述区域不存在接地故障时，采用离线测量或在线测量的方法检测所述区域的区域三相对地电纳BEA0、BEB0、BEC0；可按前述的“配电网区域对地参数测量方法”测量所述区域的区域三相对地电纳BEA0、BEB0、BEC0；
在配电网出现接地故障时，测量的所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000198
和区域对地电流
Figure PCTCN2015074276-appb-000199
利用在所述区域不存在接地故障时检测的区域三相对地电纳BEA0、BEB0、BEC0和在配电网出现接地故障时测量的所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000200
和区域对地电流
Figure PCTCN2015074276-appb-000201
根据区域三相对地电压
Figure PCTCN2015074276-appb-000202
和区域对地电流
Figure PCTCN2015074276-appb-000203
与区域对地参数之间的关系：
Figure PCTCN2015074276-appb-000204
判断所述区域是否存在接地故障；
1、配电网区一个区域的接地故障判断方法一：
针对所述区域，在配电网出现接地故障时，根据前述的“配电网区域对地参数测量方法三、四、五”测量区域三相对地电导GEA、GEB、GEC，如果测量的区域三相对地电导GEA、GEB、GEC出现异常，例如出现所述区域某相对地电导值较低，可判断所述区域范围内存在接地故障。
2、配电网中一个区域的接地故障判断方法二：
在所述区域不存在接地故障时，离线或在线测量区域三相对地电导GEA0、GEB0、GEC0和区域三相对地电纳BEA0、BEB0、BEC0；在配电网出现接地故障时，测量所述区域的区域三相对地电压
Figure PCTCN2015074276-appb-000205
和区域对地电流
Figure PCTCN2015074276-appb-000206
判断在所述区域不存在接地故障时测量得到的三相对地电导GEA0、GEB0、GEC0和三相对地电纳BEA0、BEB0、BEC0与在配电网出现接地故障时测量得到的三相对地电压
Figure PCTCN2015074276-appb-000207
和区域对地电流
Figure PCTCN2015074276-appb-000208
是否符合关系式：
Figure PCTCN2015074276-appb-000209
如果偏差较大，可确定该区域存在接地故障。
3、配电网中一个区域的接地故障判断方法三：
在所述区域不存在接地故障时，区域三相对地电导GEA0、GEB0、GEC0非常小，可忽略不计，GEA0＝GEB0＝GEC0＝0；这时区域对地电流
Figure PCTCN2015074276-appb-000210
就是区域对地电容电流
Figure PCTCN2015074276-appb-000211
上述公式就变为：
Figure PCTCN2015074276-appb-000212
利用区域三相对地电纳BEA0、BEB0、BEC0和区域三相对地电压
Figure PCTCN2015074276-appb-000213
计算区域对地电容电流理论值
Figure PCTCN2015074276-appb-000214
如果区域对地电流
Figure PCTCN2015074276-appb-000215
与区域对地电容电流理论值
Figure PCTCN2015074276-appb-000216
接近，本区域不存在接地故障，如果两者偏差较大，可确定该区域存在接地故障。
4、配电网中一个区域的接地故障判断方法四：
在所述区域不存在接地故障时，离线或在线测量区域三相对地电纳BEA0、BEB0、BEC0；
在配电网出现接地故障时，根据前述的“配电网区域对地参数测量方法二”再次测量区域三相对地电纳BEA、BEB、BEC；
将前后两次测量的区域三相对地电纳BEA0、BEB0、BEC0和BEA、BEB、BEC进行对比，如果差别较大，可以确定所述区域范围内存在接地故障。
图5是配电网接地故障区域定位系统基本原理示意图。
一、配电网接地故障区域定位系统基本原理
该系统包括电压互感器PT、零序电流互感器CT1～CT5、电压检测模块、电流检测模块、电压偏移装置、电压偏移控制装置和信号处理装置组成；其中零序电流互感器将线路划分为5个区域，CT1、CT2和CT4检测区域1的区域对地电流，CT2和CT3检测区域2的区域对地电流，CT3单独检测区域3的区域对地电流，CT4和CT5检测区域4的区域对地电流，CT5单独检测区域5的区域对地电流；零序电流互感器和电流检测模块组成电流检测装置，电流检测装置检测检测各零序电流互感器的零序电流，并将零序电流检测结果送信号处理装置。
电压检测装置由电压互感器和电压检测模块组成，电压监测装置检测区域三相对地电压
Figure PCTCN2015074276-appb-000217
并将检测结果送信号处理装置；
图中三个电容器C1、C2、C3和控制三个电容器C1、C2、C3的三个单相接触器J1、J2、J3组成的电压偏移装置；电压偏移控制装置接收信号处理装置的指令，控制电压偏移装置的动作。电压偏移装置的三个电容器C1、C2、C3的一端接地，三个电容器C1、C2、C3的另一端通过三个单相接触器J1、J2、J3分别与三相线路连接。
引入电压偏移装置的目的是人为造成配电网的三相对地电压不平衡，并且导致各区域对地电流增大，这样，一方面可获得满足线性无关需要的求解区域对地参数的方程组，另一方面区域对地电流在一定程度上增大有利于提高对地电流测量的精度，有利于提高区域对地参数的检测准确度。
信号处理装置接收来自电压检测装置的区域三相对地电压，接收来自电流检测装置的各零序电流，由信号处理装置利用各零序电流检测值计算各区域的区域对地电流
Figure PCTCN2015074276-appb-000218
在配电网不存在接地故障时，信号处理装置按前述的“配电网一个区域的区域对地参数测量方法”检测各区域的区域三相对地电纳BEA0、BEB0、BEC0；在配电网出现接地故障时，按前述的“配电网中一个区域的接地故障判断方法”分别判断各区域是否存在接地故障，从而实现配电网的接地故障区域定位功能。
二、人为改变配电网中性点对地电压的方法：
人为改变三相对地电压的方法可以是使配电网一相接地；可以是使配电网一相通过电阻、电感或电容接地；可以是在配电网中性点或人工中性点与地之间加入电阻、电感或电容；可以是使连接在配电网中性点或人工中性点与地之间的电阻、电感或电容的阻抗发生改变；可以是通过在配电网中性点或人工中性点与地之间加入偏移电源使配电网中性点对地电压发生偏移；可以是通过调整变压器的分接开关使变压器的输出电压发生中性点偏移；可以是采用上述方法的组合调整配电网三相对地电压。
图6是利用接地电阻器调整三相对地电压原理示意图
在配电网中增设三个电阻器R1、R2、R3和控制三个电阻器R1、R2、R3的三个单相接触器J1、J2、J3。三个电阻器R1、R2、R3的一端接地，三个电阻器R1、R2、R3的另一端通过三个单相接触器J1、J2、J3分别与三相线路连接。利用电阻器调整中性点对地电压的原理与利用电容器调整中性点对地电压的原理类似。也可以只设置一个电阻器，电阻器的一端接地，电阻器的另一端通过三个单相接触器与三相线路连接。
图7是利用接地电抗器调整三相对地电压原理示意图。
在配电网中增设三个电抗器L1、L2、L3和控制三个电抗器L1、L2、L3的三个单相接触器J1、J2、J3。三个电抗器L1、L2、L3的一端接地，三个电抗器L1、L2、L3的另一端通过三个单相接触器J1、J2、J3分别与三相线路连接。利用电抗器调整中性点对地电压的原理与利用电容器调整中性点对地电压的原理类似。
图8是利用接地开关调整三相对地电压原理示意图。
在配电网中增设三个单相接地开关DL1、DL2、DL3和三个熔断器RD1、RD2、RD3。三个单相接地开关DL1、DL2、DL3的一端接地，三个单相接地开关DL1、DL2、DL3的另一端通过三个熔断器RD1、RD2、RD3分别与三相线路连接。
利用单相接地开关调整中性点对地电压与利用电阻器调整中性点对地电压的原理类似，相当于电阻器的阻值为0Ω。目前有些配电网配备有单相接地开关，在系统出现接地故障时利用单相接地开关将故障相与地短接，能够起到及时熄灭电弧的作用；针对这样的系统，可以利用现有的单相接地开关实现配电网的中性点电压调整。
图9是利用串接于中性点与地之间的调压设备调整中性点对地电压原理示意图。
3个电抗器L1、L2、L3的一端分别连接三相线路，3个电抗器的另一端连接在一起形成人工中性点。在人工中性点与大地之间串接变压器T1的二次线圈；变压器T1的一次线圈的一端接380V低压系统的零线N，一次线圈的另一端可分别通过3个开关K1、K2、K3与低压系统的相线A、B、C连接。设置3个熔断器RD1、RD2、RD3起短路保护作用。分别闭合3个开关K1、K2、K3可调整待测量配电网的中性点对地电压。合理设置变压器T1的容量、变比和漏抗等参数，可以获得理想的调压效果。
图10是针对分配电室设有对地电压检测装置的配电网接地故障区域定位原理示意图
变电站设有电压互感器PT1，PT1的二次接主站电压检测装置，检测变电站母线各相对地电压；QF1为变电站的一个出线开关；QF2为分配电室的进线开关，分配电室还有两个出线开关QF3和QF4。分配电室设有电压互感器PT2，PT2的二次接分站电压检测装置，检测分配电室母线各相对地电压。
共划定6个区域，由CT1和CT2检测变电站到分配电室的电缆的对地电流；由CT2、CT3和CT5检测分配电室配电柜内的对地电流；由CT3和CT5分别检测开关QF3和QF4控制的出线回路的对地电流；QF3回路的电缆的外屏蔽层的首端通过接地线接地，尾端通过过电压保护器接地，首端接地线穿过精密电流互感器CT4，由CT4检测该条电缆的对地电流；QF4回路的电缆的外屏蔽层的首尾两端都通过接地线接地，首端的接地线穿过精密电流互感器CT6，尾端的接地线穿过精密电流互感器CT7，将CT6和CT7测量的电流按流入大地的方向矢量相加，可得到该条电缆的对地电流。
区域1采用主站电压检测装置检测的三相对地电压；区域2、区域3、区域4区域5、区域6采用分站电压检测装置检测的三相对地电压。
当变电站与分配电室距离较远，负荷电流又较大，考虑线路压降的影响，可以在分配电室设电压检测装置，减小分配电室供电范围内区域对地电压的误差，改善分配电室供电范围内接地故障区域定位的效果。
图11环网线路接地故障区域定位原理示意图
本图以两个变电站供电的环网供电系统部分线路为例，说明在环网供电时的配电网接地故障区域定位原理。两个变电站各有一套配电网接地故障区域定位系统，两个变电站还各有一套电压偏移装置。
全部线路分为12个区域，包括3个环网柜区域、8个线路区域和1个变压器区域，由13个零序电流互感器测量12个区域的区域对地电流。其中，区域1、区域4和区域9为环网柜区域，检测环网柜内部的接地故障；区域2、区域3、区域5、区域6、区域8、区域10、区域11和区域12各负责一段线路，区域7负责一台变压器；其中CT7采用三个电流互感器分别检测三相电流，由FTU通过计算获得该处的零序电流。针对架空线路、架空母线等场合，有时不方便安装零序电流互感器，可利用三相电流计算获得，但该方法测量的零序电流误差较大，可能影响判断的准确性，最好还是采用零序电流互感器。
两个变电站的三相线路对地电压由两个配电主站系统分别检测并提供给各自的配电网 接地故障区域定位系统，由环网柜开闭所远方终端(DTU)、馈线远方终端(FTU)和变压器远方终端(TTU)测量各电流检测点的零序电流的幅值和相位并分别传送给两个变电站配电主站系统，再由两个配电主站系统传送给两个配电网接地故障区域定位系统，同时两个变电站配电主站系统分别向各自的配电网接地故障区域定位系统传送本变电站的三相对地电压和本变电站的供电范围信息和线路运行方式信息，由两个站的配电网接地故障区域定位系统分别对本系统负责范围内的各区域进行对地参数测量和接地故障的区域定位。
在环网供电的情况下，两个变电站的供电范围存在相互交叉现象，例如A变电站供电范围内的部分线路和设备因为某种原因暂时由B变电站供电；这时，由B变电站供电的这些原本属于A变电站供电范围内的线路和设备的接地故障监测是需要解决的问题；可以针对这些区域，由B变电站检测这部分线路的三相对地电压，传送给A变电站的配电网接地故障区域定位系统，由A变电站处理这部分线路和设备的接地故障检测；需要利用A和B两套配电网接地故障区域定位系统之间的通讯实现相关数据的传送；
两套系统都利用GPS标准时间和秒脉冲实现三相对地电压和零序电流的相位同步检测，一方面可提高三相对地电压和零序电流的相位检测精度，提高对地参数测量精度，提高接地故障区域定位判断的准确性；另一方面也可实现两套系统之间的协调配合，解决环网供电线路的接地故障的区域定位功能。
配电网接地故障区域定位系统可以将对地参数测量和接地故障定位的结果提供给配电主站系统，由配电主站系统完成接地故障区域的隔离。当然，也可以将配电网接地故障区域定位系统的功能包括在配电主站系统中。
图12是本发明在小电阻接地系统接地故障区域定位方面的应用原理图
中性点经小电阻接地系统的中性点与地之间串接了一个阻值约为几十欧姆的电阻器R1，在系统出现接地故障时，故障电流达到几百安培，由微机保护装置检测到接地故障回路，并由断路器切除故障回路。但是如果出现高阻接地故障，可能出现接地保护拒动，如果不能实现故障区域的及时定位并隔离故障线路，可能烧坏中性点接地电阻，带来更大的安全隐患，所以对于中性点经小电阻接地系统同样需要接地故障区域定位；针对中性点经小电阻接地方式的系统，调整中性点对地电压时有必要暂时断开小电阻，这时系统变为不接地系统，可以进行三相对地电压的调整，测量各区域三相对地电纳；在参数测量期间一旦发生接地故障，应立即接通小电阻，快速切除故障线路，从而保证配电系统的安全运行；如果出现高阻接地故障，可采用前述的接地故障区域定位的方法实现接地故障的区域定位，并隔离故障区域。
中性点经小电阻接地系统的三相对地电压调整方法是：如图13所示，小电阻一端接地，另一端通过开关J4连接到中性点，在检测区域对地参数期间，断开开关J4，测量结束闭合开关J4；在测量区域对地参数期间一旦出现接地故障，立即闭合开关J4，成为小电阻接地系统，迅速切断故障回路；如果出现高阻接地故障，保护拒动，可通过本发明的接地故障区域定位方法检测存在接地故障的区域，隔离故障回路。
图13是具有上位机系统的配电网接地故障区域定位系统原理示意图
配电网接地故障区域定位系统包括上位机系统、电压检测模块、电流检测模块、带GPS授时的集中器、无线通讯模块和电压偏移装置。由电压检测模块检测区域三相对地电压；由电流检测模块检测各检测点的零序电流；带GPS的集中器一方面向电压检测模块和电流检测模块提供GPS秒脉冲实现测电压和电流的相位角的同步检测，同时采集电压和电流的检测数据，通过有线或无线方式将检测的数据传送到上位机系统；上位机系统通过电压偏移控制器控制电压偏移装置调整配电网的三相对地电压，配合配电网接地故障区域定位系统对区域对地参数的测量；由上位机系统控制配电网接地故障区域定位系统的工作，按照前述的区域对地参数测量方法检测各区域的区域对地参数，在配电网出现接地故障时，按前述的区域接地故障判断方法对每个区域进行是否存在接地故障的判断，从而实现配电网接地故障区域定位功能。可利用上位机系统实现与其他配电网接地故障区域定位系统的通讯，实现与配电自动化系统的通讯，实现与电力调度系统的通讯。
关于区域划分方法：
前面的例子基本都是采用的平行分区法，即将供配电线路划分为若干个区域，各个区域之间没有重叠，可直接判断存在接地故障的区域。
此外，还可以采用分级分区法，即将供配电网路先划分为几个大区域，再在大区域中划分出若干个小区域，在小区域中还可以再划分出若干个更小的区域。分级分区法的一个具体方案是从变电站开始逐级布置零序电流互感器，每一个零序电流互感器的检测范围包括其后的全部线路；如果某个前级零序电流互感器检测到接地故障，而其后的各个零序电流互感器都没有检测到接地故障，则接地故障位于该两级之间的区域。
图14根据本发明的配电网区域接地故障检测方法和配电网接地故障区域定位系统的仿真试验原理图
在图14中，由CT1检测区域1、区域2、区域3、区域4全部范围的对地电流，由CT2检测区域2、区域3、区域4全部范围的对地电流，由CT3检测区域3的对地电流，由CT5检测区域4的对地电流；如果CT1检测到接地故障，而CT2检测结果正常，则接地故障在区域1范围内。如果CT1和CT2都检测到接地故障，则接地点在CT2之后。
中性点经消弧线圈接地系统的接地故障选线和定位难度相对较大，所以仿真实验按照中性点经消弧线圈接地系统配置，当然本发明同样适用于其他形式的小电流接地系统；
线路为10kV中性点经消弧线圈接地系统，在该系统中，由4个零序电流互感器CT1～CT4分别检测4个区域的零序电流，其中区域4是为了体现中性点经消弧线圈接地系统较大的电容电流而设置的，仿真实验只针对区域1、区域2、区域3进行。
仿真实验采用单相导线通过接地电阻接地的方式调整三相对地电压。
下面，是针对本发明的供配电网络区域对地参数测量和接地故障区域定位方法进行仿真实验的结果。
仿真实验1：采用“供配电网络区域对地参数测量方法二”检测区域三相对地电容。
设定区域内三相对地电导为0，改变中性点对地电压，测量三相对地电压
Figure PCTCN2015074276-appb-000219
和区域对地电流
Figure PCTCN2015074276-appb-000220
代入下述关系式：
UBE·sinθB·BEB+UCE·sinθC·BEC＝IE·cosθE
-UAE·BEA-UBE·cosθB·BEB-UCE·cosθC·BEC＝IE·sinθE
通过解方程可得到三相对地电纳，并转换出三相对地电容。
仿真实验中的区域对地参数如表1，消弧线圈电抗为0.2H；采用偏置电阻调整三相对地电压，偏置电阻1kΩ。
表1
  RAE RBE RCE CAE CBE CCE
区域1 100MΩ 100MΩ 100MΩ 0.010uf 0.011uf 0.012uf
区域2 50MΩ 50MΩ 50MΩ 0.12uf 0.10uf 0.11uf
区域3 20MΩ 20MΩ 20MΩ 1.1uf 1.2uf 1.0uf
区域4 10MΩ 10MΩ 10MΩ 15uf 15uf 15uf
表2为三相对地电压和区域对地电流测量数据。
表2
Figure PCTCN2015074276-appb-000221
表2中
Figure PCTCN2015074276-appb-000222
分别是区域1、区域2、区域3的区域对地电流。
各区域三相对地电容的实际值与测量值见表3。
表3
Figure PCTCN2015074276-appb-000223
从计算结果来看，区域三相对地电容的测量值与实际值基本相符，所以采用“供配电网络区域对地参数测量方法二”可以实现区域内三相对地电容的检测。
仿真实验2：采用“供配电网络区域对地参数测量方法三”检测区域三相对地电阻。
已知区域三相对地电容；在供配电网络出现接地故障时，改变中性点对地电压，测量三相对地电压
Figure PCTCN2015074276-appb-000224
和区域对地电流
Figure PCTCN2015074276-appb-000225
将三相对地电压和区域对地电流连同已知的区域三相对地电容代入下述关系式：
UAE·GEA+UBE·cosθB·GEB+UCE·cosθC·GEC
＝IE·cosθE-UBE·sinθB·BEB-UCE·sinθC·BEC
UBE·sinθB·GEB+UCE·sinθC·GEC
＝IE·sinθE+UAE·BEA+UBE·cosθB·BEB+UCE·cosθC·BEC
通过解方程可得到三相对地电导，并转换出三相对地电阻。
仿真实验中的区域对地参数如表4，消弧线圈电抗为0.2H；采用偏置电阻调整三相对地电压，偏置电阻1kΩ。在区域1和区域3各设置一个接地故障，故障电阻10kΩ，。
表4
Figure PCTCN2015074276-appb-000226
表5为三相对地电压和区域对地电流测量数据。
表5
Figure PCTCN2015074276-appb-000227
表5中
Figure PCTCN2015074276-appb-000228
分别是区域1、区域2、区域3的区域对地电流。
各区域的三相对地电阻REA、REB、REC的实际值与测量值见表6。
表6
Figure PCTCN2015074276-appb-000229
从计算结果看，“区域1”A相和“区域3”C相的对地电阻测量值接近10kΩ，与实际值基本相符；其他对地电阻的阻值相对较高；所以该方法可以检测接地过渡电阻的阻值，并可据此判断存在接地故障的区域。
仿真实验3：采用本发明的“供配电网络区域对地参数测量方法四”检测接地故障相的对地电阻和三相对地电容的仿真实验。
“供配电网络区域对地参数测量方法四”是在供配电网络出现接地故障后，先判断那一相存在接地故障，例如已知C相存在接地故障，可设A相、B相的对地电导为0；改变中性点对地电压，测量三相对地电压
Figure PCTCN2015074276-appb-000230
和区域对地电流
Figure PCTCN2015074276-appb-000231
代入下述方程式：
UCE·cosθC·GEC+UBE·sinθB·BEB+UCE·sinθC·BEC＝IE·cosθE
UCE·sinθC·GEC-UAE·BEA-UBE·cosθB·BEB-UCE·cosθC·BEC＝IE·sinθE
通过解方程，可计算出C相对地电导GEC和三相对地电纳BEA、BEB、BEC，并可转换出C相对地电阻RCE和三相对地电容CEA、CEB、CEC。
在“仿真实验2”中，在“区域1”的A相和“区域3”的C相设置了接地故障，并进行了三相对地电压
Figure PCTCN2015074276-appb-000232
和区域对地电流
Figure PCTCN2015074276-appb-000233
的调整和测试，在此，利用“仿真实验2”的表5的实验数据针对“区域3”的C相进行对地电导GEC和三相对地电纳BEA、BEB、BEC进行计算，计算结果转换为C相电阻和三相对地电容。“区域3”的C相对地电阻和三相对地电容的实际值与测量值见表7。
表7
参数 区域3实际值 区域3测量值
RCE 10kΩ 9.85kΩ
CAE 1.1uf 1.103uf
CBE 1.2uf 1.207uf
CCE 1.0uf 0.996uf
从测量结果看，“区域3”的C相对地电阻为9.85kΩ，接近10kΩ，三相对地电容CEA、CEB、CEC也与实际值相近，所以该方法可以检测故障区的接地过渡电阻值以及三相对地电容值。
仿真实验4：采用本发明的“供配电网络区域对地参数测量方法五”检测接地故障相的对地电阻的仿真实验。
已知三相对地电容；在供配电网络出现接地故障后，先判断那一相存在接地故障，例如已知C相存在接地故障，可设A相、B相的对地电导为0；测量三相对地电压
Figure PCTCN2015074276-appb-000234
和区域对地电流
Figure PCTCN2015074276-appb-000235
将三相对地电压和区域对地电流连同已知的区域三相对地电容代入下述方程式：
UCE·cosθC·GEC＝IE·cosθE-UBE·sinθB·BEB-UCE·sinθC·BEC
UCE·sinθC·GEC＝IE·sinθE+UAE·BEA+UBE·cosθB·BEB+UCE·cosθC·BEC
通过解方程，可计算出C相对地电导GEC，并可转换出C相对地电阻RCE。
仿真实验中的区域对地参数如表8，消弧线圈电抗为0.2H；采用偏置电阻调整三相对地电压，偏置电阻1kΩ。在“区域3”的C相设置一个接地故障，故障电阻100Ω。
表8
Figure PCTCN2015074276-appb-000236
表9为三相对地电压和区域对地电流测量数据。
表9
Figure PCTCN2015074276-appb-000237
Figure PCTCN2015074276-appb-000238
表9中
Figure PCTCN2015074276-appb-000239
分别是区域1、区域2、区域3的区域对地电流。
各区域的C相对地电阻REC的实际值与测量值见表10。
表10
参数 REC的实际值 REC的测量值
区域1 100MΩ -9057kΩ
区域2 50MΩ -44.7kΩ
区域3 100Ω 100.12Ω
区域3的C相对地电阻的计算结果是：RCE＝100.12Ω，与实际值接近；其他区域的C相对地电阻较大；所以该方法可以检测故障区的接地过渡电阻值。
仿真实验5：采用本发明的“供配电网络接地故障区域定位方法四”判断区域范围内是否存在接地故障的仿真实验。
“供配电网络接地故障区域定位方法四”是在所述区域不存在接地故障时，测量区域范围内三相对地电纳BEA、BEB、BEC；在供配电网络出现接地故障时，测量所述区域的三相对地电压
Figure PCTCN2015074276-appb-000240
和区域对地电流
Figure PCTCN2015074276-appb-000241
判断在所述区域不存在接地故障时测量得到的三相对地电纳BEA、BEB、BEC与在供配电网络出现接地故障时测量得到的该区域的三相对地电压
Figure PCTCN2015074276-appb-000242
和区域对地电流
Figure PCTCN2015074276-appb-000243
是否符合关系式：
Figure PCTCN2015074276-appb-000244
在“仿真实验4”中在“区域3”的C相设置了接地故障，并进行了三相对地电压
Figure PCTCN2015074276-appb-000245
和区域对地电流
Figure PCTCN2015074276-appb-000246
的调整和测试，在此，利用“仿真实验4”的表9的实验数据计算出各区域的区域对地电流的理论值。各区域的区域对地电流理论计算值和实际测量值见表11。
表11
Figure PCTCN2015074276-appb-000247
“区域3”的区域对地电流理论值
Figure PCTCN2015074276-appb-000248
与区域对地电流实际测量值
Figure PCTCN2015074276-appb-000249
在有效值和相位方面相差相对较大，可以依此得出结论：“区域3”存在接地故障。
仿真实验6：采用“供配电网络接地故障区域定位方法五”判断区域内是否存在接地故障的仿真实验
“供配电网络接地故障区域定位方法五”是在所述区域不存在接地故障时，测量区域范 围内三相对地电纳BEA、BEB、BEC，在供配电网络出现接地故障时，再次测量区域范围内三相对地电纳BEA、BEB、BEC，对比前后两次测量结果，判断区域范围内是否存在接地故障。
本仿真实验方法是：出现接地故障后，采用“供配电网络区域对地参数测量方法二”测量区域范围内三相对地电纳BEA、BEB、BEC。将出现接地故障时的三相对地电压和区域对地电流作为一组测量数据，闭合A相偏置电阻后再测量一组三相对地电压和区域对地电流的数据，利用两组数据进行计算。
仿真实验中的区域对地参数如表12，消弧线圈电抗为0.2H；采用偏置电阻调整三相对地电压，偏置电阻1kΩ。在“区域3”设置一个接地故障，故障电阻2kΩ。
表12
Figure PCTCN2015074276-appb-000250
表13为三相对地电压和区域对地电流测量数据。
表13
Figure PCTCN2015074276-appb-000251
表13中
Figure PCTCN2015074276-appb-000252
分别是区域1、区域2、区域3的区域对地电流。
表14是故障前后区域三相对地电容的对比。
表14
Figure PCTCN2015074276-appb-000253
“区域3”的三相对地电容在故障前后相差较大，而其他区域的三相对地电容在故障前后变化很小，据此可以判断“区域3”为存在接地故障区域。
从上述6个仿真实验的结果看，采用本发明的供配电网络区域对地参数测量和接地故障区域定位方法原理正确，效果较好。
本发明的区域线路对地参数测量方法不限于进行接地故障的查找和定位，还可以应用到其他方面，例如可用于对配电网分布电容的测量，为消弧线圈的调整提供依据；只要应用多 次测量三相对地电压和区域对地电流进行区域对地参数计算，均属于本发明的保护范围。
本发明的接地故障区域定位方法不限于前述的方法，只要是针对电力线路的部分区域或区段，通过测量区内线路的对地参数进行接地故障的判断、定位或保护，都属于本发明的保护范围。
本发明的配电网区域接地故障检测方法和配电网接地故障区域定位系统不仅限于前述的范围，例如在中性点或人工中性点与地之间施加偏移电压的方法不限于本文中的描述，例如可以利用逆变电源为电压偏移变压器供电；投切偏移负载不仅可以使用机械开关，还可以采用可控硅投切等其他投切方式。只要利用人为调整中性点对地电压的方法测量区域对地参数和进行接地故障判断、定位，都属于本发明的保护范围。

Claims (21)

  1. 一种配电网区域接地故障检测方法，其特征是：
    在配电网中划定一个区域，所述区域中可以只包括一台设备或一段线路，也可以包括相连并相邻的若干台设备和若干段线路；
    采用离线检测或在线检测的方法测量所述区域的区域三相对地电纳BEA0、BEB0、BEC0；
    利用电压检测装置检测所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100001
    利用电流检测装置检测流入所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100002
    在配电网出现接地故障期间，利用所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100003
    区域对地电流
    Figure PCTCN2015074276-appb-100004
    和区域三相对地电纳BEA0、BEB0、BEC0，判断所述区域是否存在接地故障。
  2. 根据权利要求1所述的配电网区域接地故障检测方法，其特征是：
    针对所述区域，区域三相对地电压
    Figure PCTCN2015074276-appb-100005
    区域对地电流
    Figure PCTCN2015074276-appb-100006
    和区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间存在以下关系：
    Figure PCTCN2015074276-appb-100007
    在所述区域不存在接地故障期间，区域三相对地电导GEA0＝GEB0＝GEC0＝0；这时区域对地电流
    Figure PCTCN2015074276-appb-100008
    即是区域电容电流
    Figure PCTCN2015074276-appb-100009
    区域三相对地电压
    Figure PCTCN2015074276-appb-100010
    区域对地电流
    Figure PCTCN2015074276-appb-100011
    和区域三相对地电纳BEA0、BEB0、BEC0之间存在以下关系：
    Figure PCTCN2015074276-appb-100012
    利用这个关系式，在不同的区域三相对地电压
    Figure PCTCN2015074276-appb-100013
    下，测量多组区域三相对地电压
    Figure PCTCN2015074276-appb-100014
    和区域电容电流
    Figure PCTCN2015074276-appb-100015
    每组数据可形成一个求解区域三相对地电纳BEA0、BEB0、BEC0的方程，通过解方程，可以得到所述区域的区域三相对地电纳BEA0、BEB0、BEC0。
  3. 根据权利要求2所述的配电网区域接地故障检测方法，其特征是：
    针对类似三相电缆这样的三相对地电纳BEA0、BEB0、BEC0对称性比较好的设备，三相对地电纳相等，即BEA0＝BEB0＝BEC0，这时区域三相对地电压
    Figure PCTCN2015074276-appb-100016
    区域对地电容电流
    Figure PCTCN2015074276-appb-100017
    区域三相对地电纳BEA0、BEB0、BEC0之间的关系式：
    Figure PCTCN2015074276-appb-100018
    就变为：
    Figure PCTCN2015074276-appb-100019
    由于
    Figure PCTCN2015074276-appb-100020
    所以该关系式又可以变为：
    Figure PCTCN2015074276-appb-100021
    可以利用后两个关系式在线测量区域三相对地电纳BEA0、BEB0、BEC0。
  4. 根据权利要求1～3之一所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障期间，如果所述区域不存在接地故障，所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100022
    等于所述区域的区域对地电容电流
    Figure PCTCN2015074276-appb-100023
    如果所述区域存在接地故障，这时区域对地电流
    Figure PCTCN2015074276-appb-100024
    将由区域对地电容电流
    Figure PCTCN2015074276-appb-100025
    和经过接地故障点流入大地的接地故障电流组成；由于接地故障电流的加入，所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100026
    与所述区域的区域对地电容电流
    Figure PCTCN2015074276-appb-100027
    不再相等；可据此判断所述区域是否存在接地故障。
  5. 根据权利要求4所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障期间，实时检测的区域三相对地电压
    Figure PCTCN2015074276-appb-100028
    和区域对地电流
    Figure PCTCN2015074276-appb-100029
    利用区域三相对地电压
    Figure PCTCN2015074276-appb-100030
    和区域三相对地电纳BEA0、BEB0、BEC0计算所述区域的区域电容电流理论值
    Figure PCTCN2015074276-appb-100031
    Figure PCTCN2015074276-appb-100032
    将计算的区域电容电流的理论值
    Figure PCTCN2015074276-appb-100033
    与实际测量的区域对地电流
    Figure PCTCN2015074276-appb-100034
    相比较，如果区域电容电流的理论值
    Figure PCTCN2015074276-appb-100035
    与区域对地电流
    Figure PCTCN2015074276-appb-100036
    接近，则本区域范围内不存在接地故障；如果区域电容电流的理论值
    Figure PCTCN2015074276-appb-100037
    与区域对地电流
    Figure PCTCN2015074276-appb-100038
    之间相差较大，则本区域范围内存在接地故障。
  6. 根据权利要求1～3之一所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障时，假设所述区域不存在接地故障，区域三相对地电导GEA＝GEB＝GEC＝0，这时区域三相对地电压
    Figure PCTCN2015074276-appb-100039
    区域对地电流
    Figure PCTCN2015074276-appb-100040
    和区域三相对地电纳BEA、BEB、BEC之间的存在以下关系：
    Figure PCTCN2015074276-appb-100041
    利用这个关系式，在不同的区域三相对地电压
    Figure PCTCN2015074276-appb-100042
    下，测量多组区域三相对地电压
    Figure PCTCN2015074276-appb-100043
    和对应的区域对地电流
    Figure PCTCN2015074276-appb-100044
    的数据，每组数据可形成一个求解区域三相对地电纳BEA、BEB、BEC的方程，通过解方程，可以求解出所述区域的区域三相对地电纳BEA、BEB、BEC；如果所述区域范围内不存在接地故障，所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100045
    等于所述区域的区域对地电容电流
    Figure PCTCN2015074276-appb-100046
    检测的区域三相对地电纳BEA、BEB、BEC与之前测量的区域三相对地电纳BEA0、BEB0、BEC0应该接近；如果所述区域范围内存在接地故障，由于故障电流的加入，所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100047
    与所述区域的区域对地电容电流
    Figure PCTCN2015074276-appb-100048
    不再相等，检测的区域三相对地电纳BEA、BEB、BEC与之前测量的区域三相对地电纳BEA0、BEB0、BEC0之间应该存在较大的差异；可据此判断所述区域是否存在接地故障。
  7. 根据权利要求1～3之一所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障期间，如果所述区域不存在接地故障，所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100049
    等于所述区域的区域对地电容电流
    Figure PCTCN2015074276-appb-100050
    如果所述区域存在接地故障， 这时区域对地电流
    Figure PCTCN2015074276-appb-100051
    将由区域对地电容电流
    Figure PCTCN2015074276-appb-100052
    和由接地故障点流入大地的故障电流组成；这时，可利用区域三相对地电压
    Figure PCTCN2015074276-appb-100053
    区域对地电流
    Figure PCTCN2015074276-appb-100054
    和区域三相对地电纳BEA、BEB、BEC和区域三相对地电导GEA、GEB、GEC之间的关系，在线测量区域三相对地电导GEA、GEB、GEC，根据测量结果判断所述区域是否存在接地故障。
  8. 根据权利要求7所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障期间，所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100055
    区域对地电流
    Figure PCTCN2015074276-appb-100056
    和区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间存在以下关系：
    Figure PCTCN2015074276-appb-100057
    将区域三相对地电纳BEA0、BEB0、BEC0作为已知值代入，可得到求解区域三相对地电导GEA、GEB、GEC的方程式：
    Figure PCTCN2015074276-appb-100058
    将已知的区域三相对地电纳BEA0、BEB0、BEC0代入，得到下述关系式：
    Figure PCTCN2015074276-appb-100059
    利用这个关系式，在不同的区域三相对地电压
    Figure PCTCN2015074276-appb-100060
    下，测量多组区域三相对地电压
    Figure PCTCN2015074276-appb-100061
    区域对地电流
    Figure PCTCN2015074276-appb-100062
    的数据，每组数据可形成一个求解区域三相对地电导GEA、GEB、GEC的方程，通过解方程，可以求解出所述区域的区域三相对地电导GEA、GEB、GEC；如果区域三相对地电导GEA、GEB、GEC中出现较大值，或者区域三相对地电导GEA、GEB、GEC之间不平衡率较大，可判定该区域存在接地故障。
  9. 根据权利要求7所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障时，首先判断哪一相存在接地故障；
    假设已经确定配电网的C相出现接地故障，可设定所述区域的A相和B相的区域对地电导GEA、GEB为0，即GEA＝GEB＝0；前述的区域三相对地电压
    Figure PCTCN2015074276-appb-100063
    和区域对地电流
    Figure PCTCN2015074276-appb-100064
    与区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间的关系：
    Figure PCTCN2015074276-appb-100065
    变为求解C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC关系式：
    Figure PCTCN2015074276-appb-100066
    利用这个关系式，在不同的区域三相对地电压
    Figure PCTCN2015074276-appb-100067
    下，测量多组区域三相对地电压
    Figure PCTCN2015074276-appb-100068
    区域对地电流
    Figure PCTCN2015074276-appb-100069
    的数据，每组数据可形成一个求解区域C相对地电导GEC和区域三相对地电纳BEA、BEB、BEC的方程，通过解方程，可以求解出所述区域的区域C相对地电导GEC和区域三相对地电纳 BEA、BEB、BEC；如果区域C相对地电导GEC数值较大，可判定该区域存在接地故障。
  10. 根据权利要求7所述的配电网区域接地故障检测方法，其特征是：
    在配电网出现接地故障时，首先判断哪一相存在接地故障；
    假设已经确定配电网的C相出现接地故障，可设定所述区域的A相和B相的区域对地电导GEA、GEB为0，即GEA＝GEB＝0；前述的三相对地电压
    Figure PCTCN2015074276-appb-100070
    和区域对地电流
    Figure PCTCN2015074276-appb-100071
    与区域三相对地电纳BEA、BEB、BEC、区域三相对地电导GEA、GEB、GEC之间的关系：
    Figure PCTCN2015074276-appb-100072
    变为求解区域C相对地电导GEC的关系式：
    Figure PCTCN2015074276-appb-100073
    将已知的区域三相对地电纳BEA0、BEB0、BEC0代入，得到下述关系式：
    Figure PCTCN2015074276-appb-100074
    在同一时刻检测三相对地电压
    Figure PCTCN2015074276-appb-100075
    和区域对地电流
    Figure PCTCN2015074276-appb-100076
    将检测的结果代入上述关系式可形成求解区域C相对地电导GEC的方程，可计算出区域C相对地电导GEC；如果区域C相对地电导GEC数值较大，可判定该区域存在接地故障。
  11. 根据权利要求1～10之一所述的配电网区域接地故障检测方法，其特征是：
    针对所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100077
    的测量方法是：可以在区域内测量所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100078
    也可以在所述区域外测量与所述区域内三相线路存在电连接关系的三相导体的三相对地电压
    Figure PCTCN2015074276-appb-100079
    利用区域外的测量结果计算区域内的区域三相对地电压
    Figure PCTCN2015074276-appb-100080
    还可以将区域外的测量结果直接作为区域内的区域三相对地电压
    Figure PCTCN2015074276-appb-100081
    加以利用。
  12. 根据权利要求1～10之一所述的配电网区域接地故障检测方法，其特征是：
    针对所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100082
    的检测方法是：在所述区域与其他区域交界处安装电流检测装置，利用电流检测装置检测从其他区域流入所述区域的零序电流，将全部流入所述区域的零序电流按零序电流流入所述区域的方向矢量相加，可得到所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100083
  13. 根据权利要求1～10之一所述的配电网区域接地故障检测方法，其特征是：
    针对所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100084
    的检测方法是：在所述区域范围内，各相导体与大地之间存在一个设备地，设备地与各相导体之间处于绝缘状态，设备地与 大地之间也处于绝缘状态，设备地可通过一条或多条接地线与大地连接；利用电流检测装置检测流过设备地与大地之间的各条接地线的电流，将流过各条接地线的电流按流入大地的方向矢量相加，可得到所述区域的区域对地电流
    Figure PCTCN2015074276-appb-100085
  14. 根据权利要求1～10之一所述的配电网区域接地故障检测方法，其特征是：
    可以采用人为调整配电网的三相对地电压
    Figure PCTCN2015074276-appb-100086
    的方法配合区域三相对地参数的检测，每改变一次三相对地电压
    Figure PCTCN2015074276-appb-100087
    测量一次所述区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100088
    和区域对地电流
    Figure PCTCN2015074276-appb-100089
    形成求解所述区域的区域三相对地参数的线性不相关的方程组，通过解方程，可以获得所述区域的区域三相对地参数，从而实现可以随时进行区域三相对地参数的检测，并且提高检测精度的目的。
  15. 根据权利要求14所述的配电网区域接地故障检测方法，其特征是：
    人为调整配电网三相对地电压的方法可以是使配电网一相接地；可以是使配电网一相通过电阻、电感或电容接地；可以是在配电网中性点或人工中性点与地之间加入电阻、电感或电容；可以是使连接在配电网中性点或人工中性点与地之间的电阻、电感或电容的阻抗发生改变；可以是通过在配电网中性点或人工中性点与地之间加入偏移电源使配电网中性点对地电压发生偏移；可以是通过调整变压器的分接开关使变压器的输出电压发生中性点偏移；可以是采用上述方法的组合调整配电网三相对地电压。
  16. 一种配电网接地故障区域定位系统，其特征是：
    所述配电网接地故障区域定位系统在配电网中划分不同的区域，按照权利要求1～15所述的配电网区域接地故障检测方法中的一种方法或几种方法，分别针对每个区域检测本区域范围内是否存在接地故障，确定接地故障在哪个区域，或确定接地故障在所检测的这些区域之外，从而实现配电网接地故障区域定位功能。
  17. 根据权利要求16所述的配电网接地故障区域定位系统，其特征是：
    所述配电网接地故障区域定位系统包括电压检测装置、电流检测装置、电压偏移装置和配电网接地故障区域定位装置；利用分布安装的电流检测装置在配电网中划定不同的区域；由电压检测装置检测各区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100090
    由电流检测装置检测各电流检测点的电流；由配电网接地故障区域定位装置接收来自电压检测装置和电流检测装置的检测数据，经过处理得到各区域的区域三相对地电压
    Figure PCTCN2015074276-appb-100091
    和各区域的区域对地电流
    Figure PCTCN2015074276-appb-100092
    电压偏移装置可根据配电网接地故障区域定位装置的指令调整配电网的三相对地电压；所述配电网接地故障区域定位系统按照权利要求1～15所述的配电网区域接地故障检测方法中的一种方法或几种方法，分别针对每个区域检测本区域范围内是 否存在接地故障，从而实现配电网接地故障区域定位功能。
  18. 根据权利要求17所述的配电网接地故障区域定位系统，其特征是：
    所述电压偏移装置可以是能够使配电网一相接地的装置；可以是能够使配电网的一相通过电阻器、电抗器或电容器接地的装置；可以是能够使电阻器、电抗器或电容器串接在供配电网络的中性点或人工中性点与地之间的装置；可以是能够使串接在供配电网络的中性点或人工中性点与地之间的电阻器、电抗器或电容器的阻抗发生改变的装置；可以是连接于配电网的中性点或人工中性点与地之间调压设备，该设备能够使供配电网络中性点对地电压发生偏移；可以是一台能够输出三相对称电压并且可以调整三相对地电压的三相电源；也可以是上述装置的组合。
  19. 根据权利要求18所述的配电网接地故障区域定位系统，其特征是：
    所述的电压偏移装置还包括控制所述电压偏移装置的电压偏移控制装置，所述电压偏移控制装置能够根据配电网接地故障区域定位装置的指令控制所述电压偏移装置改变配电网的三相对地电压
    Figure PCTCN2015074276-appb-100093
    配合配电网接地故障区域定位系统实现配电网接地故障区域定位功能。
  20. 根据权利要求19所述的配电网接地故障区域定位系统，其特征是：
    所述的配电网接地故障区域定位系统还包括信号输出装置，可由信号输出装置将区域对地参数传送给配电网中的开关装置；或由信号输出装置将区域对地参数传送给供配电自动化系统；或由信号输出装置将区域对地参数传送给上位机系统；或由信号输出装置将接地故障所在区域信息传送给供配电网络中的开关装置，由开关装置隔离存在接地故障的区域；或由信号输出装置将接地故障所在区域信息传送给供配电自动化系统，由供配电自动化系统隔离存在接地故障的区域；或由信号输出装置将接地故障所在区域信息传送到上位机系统，由供配电网络的运行人员安排相关设备的操作，隔离存在接地故障的区域。
  21. 根据权利要求19所述的配电网接地故障区域定位系统，其特征是：
    所述的配电网接地故障区域定位系统还包括信号输入装置，所述信号输入装置可以接收来自上位机系统的信息；或接收来自配电自动化系统的信息；或接收来自开关装置的信息；所述的配电网接地故障区域定位系统可以根据接收的信息调整相关数据，或根据接收的信息调整内部的工作状态，或根据接受的信息进行相关的操作。
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