Summary of the invention
Purpose of the present invention is exactly need add special signal generation apparatus and signal supervisory instrument and defective higher to the technical requirement of injecting signal supervisory instrument and that be subject to disturb in order to solve at present for injecting AC signal, the also signal of residual voltage when making full use of fault, the route selection orientation problem when solving high transition Resistance Fault also, provide a kind of behind power distribution network generation singlephase earth fault, neutral point voltage-to-ground when utilizing fault provides power supply for the generation of direct current signal, inject direct current to failure system, realize the direct current injection type route selecting positioning system and the method thereof of failure line selection and positioning function by the current intelligence that detects direct current signal.
For achieving the above object, the present invention adopts following technical scheme:
A kind of direct current injection type route selecting positioning system, it comprises grounding transformer, DC current generator, control device and fault detector FD; Wherein grounding transformer is received on the system busbar, gets the power supply of neutral point voltage-to-ground as the DC current generator when being used for the system failure, and injects direct current by the primary winding of grounding transformer to failure system; Connect the DC current generator between the neutral point N of grounding transformer primary side and the earth, control device is received the secondary side of bus-bar potential transformer, whether the monitoring distribution system singlephase earth fault takes place, and the switching of control DC current, measure to inject the size of DC current simultaneously, according to the size of the DC current of the size adjustment injection of survey DC current; Fault detector FD is installed on the outlet of every feeder line, keeps at a certain distance away on the feeder line fault detector FD also is installed, and is used for detecting the DC current of injection, selects faulty line and localization of fault.
Described DC current generator is made of silicon stack D series resistor R and fling-cut switch K, direct current measurement sensor MA, silicon stack D rectification produces DC current, and the crosstalk resistance R of institute is a current-limiting resistance, uses variable resistor, by regulating the size of current-limiting resistance, reach and adjust the purpose of injecting the DC current size; Fling-cut switch K is used to control the input and the excision of DC current; Direct current measurement sensor MA is used for measuring the size of injecting direct current, the size of regulating current-limiting resistance R according to its measured value.
A kind of route selection localization method of direct current injection type route selecting positioning system,
Singlephase earth fault when taking place in a, and grounding transformer primary side neutral point voltage-to-ground raises, along with the trouble spot transition resistance varies in size and difference, and the highest phase voltage that is elevated to, this voltage provides power supply for the constant current generator;
B control device gauge tap K closure, neutral point voltage-to-ground are added on the DC current generator and produce direct current, and inject failure system by the primary winding of grounding transformer;
C simultaneously, control device is measured the grounding transformer primary side neutral point DC current on the branch road over the ground, and regulates the size of current-limiting resistance according to the requirement of fault detector FD sensitivity, thereby makes the DC current of injected system adjusted;
The DC current that d injects forms the loop mutually and between the trouble spot in grounding transformer primary side neutral point, winding of grounding transformer, faulty line fault, promptly have only the fault of fault feeder to form path for DC current mutually, be installed on the indication situation of the fault detector FD in feeder line exit by observation, what the DC current indication was maximum is faulty line, realizes the function of failure line selection;
After e selected faulty line, along the indication situation that faulty line is observed fault detector, fault section was having indicating fault and is not having on the section of indicating fault, Here it is fault location function, and distance is more little between two fault detectors, and bearing accuracy is high more;
F works as faulty line and is selected and has found the trouble spot, and control section gauge tap K disconnects the power supply of excision DC current generator and stops direct current and injects.
The present invention is made up of grounding transformer, DC current generator, control section and fault detector FD.Grounding transformer is received on the system busbar, gets the power supply of neutral point voltage-to-ground as the DC current generator when being used for the system failure, and injects direct current by the primary winding of grounding transformer to failure system.Connect the DC current generator between the neutral point N of grounding transformer primary side and the earth, constitute by silicon stack D series resistor R and fling-cut switch K.Silicon stack D is used for rectification and produces DC current, and the crosstalk resistance R of institute is a current-limiting resistance, uses variable resistor, by regulating the size of current-limiting resistance, reaches and adjusts the purpose of injecting the DC current size; Fling-cut switch K is used to control the input and the excision of DC current.MA is the direct current measurement sensor, is used for measuring the size of injecting direct current, the size of regulating current-limiting resistance R according to its measured value.Control section is received the secondary side of bus-bar potential transformer, whether the monitoring distribution system singlephase earth fault takes place, and the switching by fling-cut switch control DC current, measure the size of injecting DC current simultaneously, according to the size adjustment current-limiting resistance of survey DC current, thus the size of the DC current that adjusting is injected.Fault detector FD is used for detecting the DC current of injection, is installed on the outlet of every feeder line, is used to select faulty line, whenever as shown in Figure 1 all install mutually, road along the line keep at a certain distance away each mutually on installing fault detector FD, be used for localization of fault.
The direct current injection type route selecting positioning principle is as follows, when power distribution network normally moves, and system's symmetry, three phase-to-ground voltages are phase voltage, grounding transformer primary side neutral point voltage-to-ground is zero, and dc generator and system disconnect, and the DC current generator is not worked.When singlephase earth fault took place, grounding transformer primary side neutral point voltage-to-ground raise, along with the trouble spot transition resistance varies in size and difference, and the highest phase voltage that is elevated to, this voltage provides power supply for the constant current generator.Detailed process is described below: when control section detects system's generation singlephase earth fault, control section gauge tap K closure, the neutral point voltage-to-ground is added on the DC current generator and produces direct current, and injects failure system by the primary winding of grounding transformer.Simultaneously, control section is measured the grounding transformer primary side neutral point DC current on the branch road over the ground, and regulates the size of current-limiting resistance according to the requirement of fault detector FD sensitivity, thereby makes the DC current of injected system adjusted.Suppose that singlephase earth fault takes place feeder line n among Fig. 1, the flow cycle of DC current is shown in Fig. 1 dotted line, as seen the DC current of Zhu Ruing forms the loop mutually and between the trouble spot in grounding transformer primary side neutral point, winding of grounding transformer, faulty line fault, promptly have only the fault of fault feeder to form path for DC current mutually, therefore observe the indication situation of the fault detector FD that is installed on the feeder line exit, what the DC current indication was maximum is faulty line, realizes the function of failure line selection.After selecting faulty line, along the indication situation that faulty line is observed fault detector, fault section is having indicating fault and is not having on the section of indicating fault, Here it is fault location function, and distance is more little between two fault detectors, and bearing accuracy is high more.When faulty line is selected and has found the trouble spot, control section gauge tap K disconnects the power supply of excision DC current generator and stops direct current and injects.
The invention has the beneficial effects as follows:
The non-vanishing characteristics of neutral point voltage-to-ground that produce when (1) utilizing fault dexterously allow it provide power supply for direct-flow signal generator, and utilize the primary winding of grounding transformer that direct current is injected failure system;
(2) because the DC current of injecting only has flow cycle mutually in the fault of faulty line, so have DC current to flow through in the faulty line and do not have DC current to flow through in the non-fault line, make failure criterion significant difference between faulty line and the non-fault line, thereby improved the order of accuarcy of route selection;
(3) characteristics according to the DC current flow cycle can realize localization of fault, and utilization of the present invention realizes localization of fault in each method that fault detector is installed that keeps at a certain distance away on mutually of circuit;
(4) the route selection orientation problem in the time of can solving high transition Resistance Fault;
(5) regulate the size of injecting DC current adaptively according to the requirement of fault detector detection DC current sensitivity, both satisfied the requirement of detection sensitivity, do not make the DC current that flows through on the circuit excessive again.
Embodiment
The present invention will be further described below in conjunction with accompanying drawing and embodiment.
Among Fig. 1, direct current injection type route selecting positioning system comprises grounding transformer 1, DC current generator, control device 2 and fault detector FD4; Wherein grounding transformer 1 is received on the system busbar, gets the power supply of neutral point voltage-to-ground as the DC current generator when being used for the system failure, and injects direct current by the primary winding of grounding transformer 1 to failure system; Connect the DC current generator between the neutral point N of grounding transformer 1 primary side and the earth, control device 2 is received the secondary side of bus-bar potential transformer 3, whether the monitoring distribution system singlephase earth fault takes place, and the switching of control DC current, measure to inject the size of DC current simultaneously, according to the size of the DC current of the size adjustment injection of survey DC current; Fault detector FD 4 is installed on the outlet of every feeder line, keeps at a certain distance away on the feeder line fault detector FD also is installed, and is used for detecting the DC current of injection, selects faulty line and localization of fault.
The DC current generator is made of silicon stack D series resistor R and fling-cut switch K, direct current measurement sensor MA, silicon stack D rectification produces DC current, and the crosstalk resistance R of institute is a current-limiting resistance, uses variable resistor, by regulating the size of current-limiting resistance, reach and adjust the purpose of injecting the DC current size; Fling-cut switch K is used to control the input and the excision of DC current; Direct current measurement sensor MA is used for measuring the size of injecting direct current, the size of regulating current-limiting resistance R according to its measured value.
A kind of route selection localization method of direct current injection type route selecting positioning system,
Singlephase earth fault when taking place in a, and grounding transformer primary side neutral point voltage-to-ground raises, along with the trouble spot transition resistance varies in size and difference, and the highest phase voltage that is elevated to, this voltage provides power supply for the constant current generator;
B control device gauge tap K closure, neutral point voltage-to-ground are added on the DC current generator and produce direct current, and inject failure system by the primary winding of grounding transformer;
C simultaneously, control device is measured the grounding transformer primary side neutral point DC current on the branch road over the ground, and regulates the size of current-limiting resistance according to the requirement of fault detector FD sensitivity, thereby makes the DC current of injected system adjusted;
The DC current that d injects forms the loop mutually and between the trouble spot in grounding transformer primary side neutral point, winding of grounding transformer, faulty line fault, promptly have only the fault of fault feeder to form path for DC current mutually, be installed on the indication situation of the fault detector FD in feeder line exit by observation, what the DC current indication was maximum is faulty line, realizes the function of failure line selection;
After e selected faulty line, along the indication situation that faulty line is observed fault detector, fault section was having indicating fault and is not having on the section of indicating fault, Here it is fault location function, and distance is more little between two fault detectors, and bearing accuracy is high more;
F works as faulty line and is selected and has found the trouble spot, and control section gauge tap K disconnects the power supply of excision DC current generator and stops direct current and injects.
The present invention not detailed description is known technology, repeats no more.
Embodiment 1:
In certain oil recovery factory one electric substation the direct current injection type route selecting positioning principle has been carried out earth test to high transition resistance situation, record is as table 1.
As can be seen from Table 1, when transition resistance was higher, the injection DC current that the trouble spot is flow through was bigger, can satisfy the requirement of fault detector accuracy of detection.Along with the increase of transition resistance, the injection direct current that the trouble spot is flow through reduces, but also can satisfy the requirement of detection sensitivity.
It can also be seen that from table 1, when DC current current-limiting resistance that generator is gone here and there changes, to injecting the big or small influential of DC current, along with the increase of institute's crosstalk resistance, DC current generator output direct current reduces, and current-limiting resistance has played the effect of injecting the DC current size of regulating, but when one timing of transition resistance, little to trouble spot DC current influence, therefore inject less DC current, also can guarantee on the faulty line accuracy of detection requirement to DC current.
The test data sheet of table 12008 ground connection project on 17, Sun. of on February