Power distribution network line fault on-line monitoring and alarming system

Abstract

The invention discloses a power distribution network line fault on-line monitoring and alarming system. The system includes a fault positioning software system and a power distribution line fault indicator. The fault positioning software system and the power distribution line fault indicator cooperate. The fault positioning software system includes an intrastation grounding line selection apparatus, a communication front-end processor, an injection signal source and an aerial conductor line fault positioning main station monitoring system. The grounding line selection apparatus and the injection signal source serve to perform single phase grounding fault positioning. The power distribution line fault indicator and a data acquisition concentrator are outrastation apparatuses. The data acquisition concentrator and the power distribution fault indicator form a subnetwork. Among the subnetworks, a monitoring system for a line via the intrastation communication front-end processor is constituted. The fault positioning software system and the power distribution line fault indicator communicate by using cascade via radio frequency. According to the invention, with the cooperation between the fault position software system on a fault line selection host computer and the power distribution fault indicator which has communication function on the line, information which indicates the position and time of the fault can be displayed within minutes of the occurrence of the fault on a geographic information system map of a monitoring center, which facilitates maintenance personnel to head to the site of the fault, eliminate the fault and increase reliability of power supply.

Description

technical field [0001] The invention relates to a line fault monitoring system, in particular to an intelligent on-line fault monitoring and alarm system for distribution network lines. Background technique [0002] With the advancement of smart grid construction, power grid companies will gradually include medium and low voltage distribution lines in the scope of monitoring, but the traditional fault indicator adopts a mechanical structure, which can only complete the location of short-circuit faults, and cannot realize real-time monitoring of lines. After a problem occurs, it is necessary to cooperate with manual line inspection to determine the location of the short-circuit fault. It is difficult to accurately locate the ground fault in the central point non-effectively grounded system, which cannot meet the needs of the power grid company. [0003] Most of the current fault indicators have the problem of single type of fault judgment and inaccurate positioning, which aff...

AI Technical Summary

Problems solved by technology

[0004] (1) Inaccurate detection of various faults

For the neutral point small current grounding system, it is difficult to detect and locate the single-phase ground fault

The traditional fault indicator does not have the ability to obtain the zero-sequence current of the line, and cannot realize the detection and location of the ground fault

[0005] (2) The accuracy of the current transformer is low

At present, these fault indicators are generally clamped directly on the line by rough fixtures to form a magnetic conduction circuit. Due to reasons such as corrosion and spring force reduction, it will inevitably lead to excessive air gaps in current transformers and unsatisfactory magnetic flux circuits. As a result, the accuracy of the current transformer is reduced, so that small current changes cannot be reflected

[0006] (3) The fault cannot be judged from the global level

Although there are several wireless transmission modules available on the market, such as GPRS, ZIGBEE, Bluetooth, etc., but either the communication cost is too high, or the communication distance is too short, or the power consumption is too large, they cannot be used well. On the fault indicator, these reasons directly lead to the fact that the fault indicators on the line are judged separately and display alarms separately, and the fault point cannot be comprehensively judged from the overall level, thereby reducing the accuracy rate

[0007] (4) Does not have the function of reporting fault information

The current overhead line and cable fault indicators generally use local methods such as flipping cards or lighting lights when a fault occurs to indicate the occurrence of a fault. This requires the power company to organize special line patrol personnel. This method greatly increases the workload of line patrol personnel (especially In the rural network environment, the line is tens of kilometers long), and there are great defects in eliminating human judgment factors and alarm real-time

[0008] (5) It is impossible to judge the disconnection fault. Since the traditional fault indicator does not have the long-distance communication function, when the line is disconnected or artificially cut off, it cannot realize positioning and alarm

[0009] In addition, in the distribution network system, there are many lines and the operation conditions are complicated. Due to natural factors such as strong wind, rain, lightning, heavy snow, surrounding environmental factors or farmers burning wheat straw and shooting guns, sudden line failures and outages can occur. line, short circuit, ground fault, inverted rod, etc., resulting in circuit breaker tripping, large-scale blackout, discharge at crossover, ground short circuit and other accidents; among them, single-phase ground fault accounts for as much as 70% of the total fault, due to the fault section ( Location) is difficult to determine, which brings great difficulties to the maintenance work of the operation and maintenance department, especially in remote areas, it is time-consuming and laborious to find

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