CN202533542U

CN202533542U - Instantaneous signal method-based power distribution line single-phase ground fault detection system

Info

Publication number: CN202533542U
Application number: CN2012201275629U
Authority: CN
Inventors: 吕强; 陈菊明
Original assignee: Beijing Semeureka Electric Co Ltd
Current assignee: Shuimu Yuanhua Electric Co ltd; Beijing Semeureka Electric Co Ltd
Priority date: 2012-03-28
Filing date: 2012-03-28
Publication date: 2012-11-14
Anticipated expiration: 2022-03-28

Abstract

Disclosed in the utility model is an instantaneous signal method-based power distribution line single-phase ground fault detection system. The system comprises: an electronic mutual inductor, which is used for collecting instantaneous currents and phase voltages of a power distribution line; a ground fault detection module, which is connected with the electronic mutual inductor and is used for separating single-phase direct earth capacitance currents from the instantaneous currents, comparing the single-phase direct earth capacitance currents with a preset threshold and determining whether there are ground faults and outputting driving signals; a controller, which is connected with the electronic mutual inductor and the ground fault detection module and is used for receiving the driving signals, determining whether inbound ground faults occur according to the phase voltages of the power distribution line and outputting corresponding switch control signals; and a switch body, which is connected with the controller and is used for carrying out opening and closing motions according to the switch control signals outputted by the controller. According to the utility model, not only can data measurement and fault determination be accurate and reliable, but also the functions of the system are comprehensive.

Description

Distribution circuit single-phase earth fault detection system based on the momentary signal method

Technical field

The utility model relates to a kind of distribution circuit single-phase earth fault detection system based on " momentary signal method ", belongs to distribution line Earth Fault Detection technical field.

Background technology

The fault that electric line takes place is singlephase earth fault mostly; Because distribution mostly is a small current neutral grounding system, behind the generation singlephase earth fault, fault current is very small; Traditional zero-sequence component determining method poor sensitivity; Rate of false alarm is high, and switch can not accurately be judged fault still out-of-bounds in play, and house dog was lost efficacy.

Especially for urban distribution network; Arc suppression coil is installed in the transformer station; Be used for the capacitance current behind the compensated line generation singlephase earth fault, the zero-sequence current component after the compensation does not almost completely have, and judges that singlephase earth fault is inaccurate; Reliability is low, and can't judge fault types such as instantaneity ground connection, intermittent earth.

The utility model content

The purpose of the utility model is to provide a kind of distribution circuit single-phase earth fault detection system based on the momentary signal method, judges problems such as inaccurate, that reliability is low with the singlephase earth fault that the solution prior art exists.

In order to address the above problem, the utility model provides following technical scheme:

The distribution circuit single-phase earth fault detection system based on the momentary signal method that the utility model provides comprises: electronic mutual inductor, the momentary current and the phase voltage that are used to gather distribution line; The Earth Fault Detection module is connected with said electronic mutual inductor, is used for separating the single-phase capacitive earth current of momentary current, and competitive list is capacitance current and the threshold value that is provided with in advance relatively, and judges whether to take place earth fault and output drive signal; Controller is connected with the Earth Fault Detection module with said electronic mutual inductor, is used to receive said drive signal, and according to the phase voltage of distribution line, judges whether to take place in the boundary earth fault and exports corresponding switch controlling signal; Switch main body is connected with said controller, is used for carrying out the divide-shut brake action according to the switch controlling signal of said controller output.

The utility model is through detect the instantaneous capacitance current of three-phase distribution circuit in real time; And utilize other multiple momentary signals as criterion; Not only can accurately judge the generation singlephase earth fault, and further the failure judgement type is also taked corresponding action whereby.It is thus clear that, the utility model not only measurement data and fault judgement accurately and reliably, and function is more comprehensive.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work property, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is that the utility model is based on the distribution circuit single-phase earth fault detection system preferred embodiment of momentary signal method and the theory structure synoptic diagram of application thereof;

Fig. 2 FB(flow block) that to be the utility model realize based on the distribution circuit single-phase earth fault detection system preferred embodiment of momentary signal method based on the distribution circuit single-phase earth fault detection method of momentary signal method.

Embodiment

The accompanying drawing and the embodiment that will combine the utility model are below carried out clear, intactly description to the technical scheme of the utility model, and obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.

Fig. 1 schematically shows the utility model based on the structure of the distribution circuit single-phase earth fault detection system preferred embodiment of momentary signal method and when using and the relation that couples of distribution line; As shown in the figure, this preferred embodiment comprises electronic mutual inductor 8, Switch main body 7, Earth Fault Detection module 6, controller 5.Wherein, electronic mutual inductor 8 couples with three-phase distribution circuit 9, is used to gather all kinds of voltage and current signals of distribution line, comprises the momentary current signal, signals such as for example single-phase capacitive earth current, quintuple harmonics, first half-wave, electric current, phase voltage.Earth Fault Detection module 6 is connected with electronic mutual inductor 8, controller 5; Be used for separating the single-phase capacitive earth current of momentary current; Competitive list is capacitance current and the threshold value (for example 10A) that is provided with in advance relatively, and judges whether to take place earth fault and output drive signal.Controller 5 is connected with Earth Fault Detection module 6 with electronic mutual inductor 8; Be used to receive drive signal; And according to the phase voltage of distribution line; Judge whether to take place in the boundary earth fault and export corresponding switch controlling signal Switch main body 7 to be connected, be used for carrying out the divide-shut brake action according to the switch controlling signal of controller 5 outputs with controller 5.

In this preferred embodiment shown in Figure 1; Controller 5 required power supplys are by voltage conversion circuit 2 supplies; Voltage conversion circuit 2 is coupled between distribution line 9 and the controller 5, and it carries out processing such as transformation, rectification or filtering to the power supply that is obtained from distribution line 9, with provisioning controller 5.

Fig. 2 shows a plurality of steps based on the distribution circuit single-phase earth fault detection method of momentary signal method that realized by preferred embodiment shown in Figure 1, and it can be realized by preferred embodiment shown in Figure 1.Distribution line is in normal course of operation; Spuious distributed capacitance is arranged between the line-to-ground; Electric capacity has been full of electric charge owing to cable line has high-tension electricity; When this circuit generation single-phase earthing, distributed capacitance forms discharge channel in the earth point position, in a few tens of milliseconds, forms instantaneous capacitor discharge electric current.Given this; In preferred embodiment shown in Figure 2,, utilize precision height, the fast characteristics of survey frequency scope of electronic mutual inductor 8 like step S101; With the sensor of electronic mutual inductor 8, gather the momentary current signal that single-phase earthing takes place distribution line 9 as front end.Like step 103, the momentary current signal passes to Earth Fault Detection module 6.Earth Fault Detection module 6 is made up of analog current and integrated chip; Form special filtering and detect electric current, be used for isolating the capacitance current component of the momentary current signal of single-phase earthing, utilize comparator circuit then; Compare with the threshold values that is provided with in advance; When detecting signal during greater than threshold values, Earth Fault Detection module 6 judges that singlephase earth fault possibly take place these circuits, and earth point takes place is positioned at the position of electronic mutual inductor 8 mounting points rear ends (mounting points is a front end to the direction of transformer station; Direction to power load is the rear end), otherwise return step S101.

Further, for fear of the undesired signal that causes owing to the load current fluctuation, like step S105,, need judge distribution line 9 phase voltage signal at that time.The phase voltage of ground connection phase is owing to be grounded a short circuit and can descend, even voltage is zero, but not the circuit of ground connection phase is owing to want retention wire voltage constant, and can raise.In conjunction with above the signal of detected instantaneous capacitance current, controller 5 judges that singlephase earth fault really takes place back end of line, also can be described as earth fault in the boundary takes place, otherwise return step S101.

Earth fault comprises permanent earth fault, intermittent earth fault, types such as transient earthing fault.For permanent earth fault, very harmful to operation of power networks, several kinds of earth faults in back need to report to the police, but constantly electric-examination is repaiied.Therefore, when detection of ground faults, need distinguish the type of earth fault.

For permanent earth fault, controller can carry out breaking-closing operating by CS, confirms in order to the method for further utilizing reclosing whether earth fault takes place in play; For example, in step S107, delayed time one minute; Certainly in other embodiments, also can delay time 30 seconds or 90 seconds etc.And in step S109, whether detection of ground faults disappears, if disappear, then gets into step S111, and controller 5 judges that this time earth fault is transient fault, and does not send control signal to Switch main body 7, and the Switch main body 7 of distribution line 9 is failure to actuate.Among the step S109, if earth fault do not disappear, then get into step S113,5 of controllers send sub-gate signal to Switch main body 7.Then in step S115, by voltage signal and current signal that controller 5 sends according to electronic mutual inductor 8, whether detection of ground faults disappears once more; If disappear, execution in step S117 then, controller 5 judges that this time earth faults are boundary's internal fault and report to the police; If do not disappear; Then execution in step S119 sends energization control signal by controller 5 to Switch main body 7, makes Switch main body 7 reclosings.

This product is a criterion with the momentary signal of electronic mutual inductor collection, utilizes it to carry out fault judgement, can accurately detect the singlephase earth fault of stake resistance≤600 Ω, and distinguishes fault still out-of-bounds in play.It is thus clear that the utility model has accurately and reliably, the advantage of complete function when detecting and handle distribution line earth fault.

The above; Be merely the embodiment of the utility model; But the protection domain of the utility model is not limited thereto; Any technician who is familiar with the present technique field can expect changing or replacement in the technical scope that the utility model discloses easily, all should be encompassed within the protection domain of the utility model.Therefore, the protection domain of the utility model answers the protection domain of said claim to be as the criterion.

Claims

1. the distribution circuit single-phase earth fault detection system based on the momentary signal method is characterized in that, comprising:

Electronic mutual inductor, the momentary current and the phase voltage that are used to gather distribution line;

The Earth Fault Detection module is connected with said electronic mutual inductor, is used for separating the single-phase capacitive earth current of momentary current, and competitive list is capacitance current and the threshold value that is provided with in advance relatively, and judges whether to take place earth fault and output drive signal;

Controller is connected with the Earth Fault Detection module with said electronic mutual inductor, is used to receive said drive signal, and according to the phase voltage of distribution line, judges whether to take place in the boundary earth fault and exports corresponding switch controlling signal;

Switch main body is connected with said controller, is used for carrying out the divide-shut brake action according to the switch controlling signal of said controller output.