CN105891686A - Alarming method for partial discharge wireless monitoring system - Google Patents

Abstract

The invention discloses an alarm method for a partial discharge wireless monitoring system, which adopts the principle of a Schmidt trigger, compares and judges real-time monitoring data with a given threshold, and can alarm for each sensor.

Description

An alarm method for a partial discharge wireless monitoring system

technical field

The invention relates to an alarm method for a partial discharge wireless monitoring system.

Background technique

With the rapid development of my country's power industry, the modern power system is developing in the direction of large power grids, large units, ultra-high voltage, and large capacity, and higher requirements are placed on the insulation level of power equipment. As an important link in the transmission and distribution system of the smart grid, the substation and distribution station implement insulation status monitoring and early warning of various electrical equipment, which can effectively improve the operation reliability of the electrical equipment in the substation and distribution station and reduce the operation of equipment. Reduce maintenance costs, prolong the service life of equipment, and reduce the incidence of accidents.

Partial discharge is one of the important data that reflects the insulation performance of key equipment in substations. It includes signs and manifestations of equipment insulation degradation, and can reflect the internal operating conditions and insulation status of electrical equipment in advance, and timely detect possible faults in the internal insulation of equipment. Potential safety hazards or defects are convenient for the staff to take targeted measures to prevent latent and sudden bad accidents. Therefore, partial discharge monitoring has been more and more widely used as an important means of insulation diagnosis.

At present, the monitoring methods of partial discharge mainly include chemical monitoring method, pulse current method, ultra-high frequency monitoring method, ultrasonic monitoring method and so on.

Chemical monitoring method: During the partial discharge process, the insulating material will be decomposed into different types of gases under the action of heat and electricity, which can be judged by detecting the concentration of different gases, such as gas chromatography detection method. However, this type of method has poor timeliness and insufficient responsiveness.

Pulse current method: detect the partial discharge of transformers, capacitors, bushings, transformers, and solid insulation structures by detecting impedance. The coverage of its detection information is incomplete, the amount of information is small, and it is easy to be interfered by various conditions on site.

Ultra-high frequency monitoring method: detect the ultra-high frequency (300-3000MHz) electrical signal generated during the partial discharge process. This method has some inherent disadvantages: the monitoring effect of partial discharge accompanied only by electromagnetic waves below 300MHz is poor; the signal attenuation is very strong when it passes through the bushing or propagates in insulating oil for a long distance, etc.

Ultrasonic monitoring method: Use ultrasonic sensors to receive ultrasonic waves generated when partial discharges occur in electrical equipment, thereby detecting the size and location of partial discharges. This method has no impact on the operation of the equipment, is more suitable for on-line monitoring, and has unique advantages in locating the discharge source of the equipment.

There are a lot of electrical equipment in high-voltage substations. At present, there are two biggest problems in partial discharge detection: the lack of effective insulation on-line monitoring methods and the difficulty of data transmission.

The monitoring system is limited by the working conditions of the sensors, and it is mostly aimed at a specific device, such as GIS equipment monitoring, switchgear equipment monitoring, etc., and it is difficult to cover all key electrical equipment in the substation, which brings inconvenience to the timely monitoring of operators .

Ultrasonic sensors are used to detect the partial discharge signal of the equipment under test. Due to the complex actual working conditions of the substation and distribution station, there are many equipment under test, and there is no effective alarm method to provide alarm service for each ultrasonic sensor.

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art and provide an alarm method for a partial discharge wireless monitoring system, which adopts the principle of a Schmidt trigger, compares and judges real-time monitoring data with a given threshold, and can target each A sensor gives an alarm.

The technical solution for achieving the above purpose is: an alarm method for a partial discharge wireless monitoring system, comprising the following steps:

Step S1, reading the partial discharge signal at a certain moment of the equipment under test monitored by the ultrasonic sensor;

Step S2, comparing the partial discharge signal at this moment with the allowable fluctuation range threshold, and judging whether the partial discharge signal at this moment exceeds the allowable fluctuation range threshold;

Step S3, when the partial discharge signal at this moment exceeds the threshold of the allowable fluctuation range, record the moment and count the time, if the duration of the real-time partial discharge signal of the device under test that exceeds the threshold of the allowable fluctuation range detected by the ultrasonic sensor reaches or exceeds the limited time When the threshold is reached, the partial discharge wireless monitoring system generates an alarm message and sends out an alarm signal for the ultrasonic sensor, and then proceeds to step S4; When it is less than the defined time threshold, proceed to step S5;

Step S4, when the real-time partial discharge signal of the device under test detected by the ultrasonic sensor drops and returns to the threshold of the allowable fluctuation range, record the time value and count the time, if the real-time partial discharge signal that returns to the threshold of the allowable fluctuation range lasts When the time exceeds the limited time threshold, record the new time value and end the alarm signal, and store the alarm information in the alarm database; if the duration of the real-time partial discharge signal restored to the allowable fluctuation range threshold is less than the limited time threshold, Then proceed to step S5;

In step S5, the display of the wireless partial discharge monitoring system outputs the real-time partial discharge signal of the device under test, and updates the time when the ultrasonic sensor monitors the real-time partial discharge signal of the device under test, and then proceeds to step S1.

The alarm method of the partial discharge wireless monitoring system of the present invention adopts the principle of a Schmidt trigger, and can issue an alarm for each sensor by comparing and judging real-time monitoring data with a given threshold.

Description of drawings

Fig. 1 is a flow chart of the alarm method of the partial discharge wireless monitoring system of the present invention.

detailed description

In order to enable those skilled in the art to better understand the technical solution of the present invention, its specific implementation will be described in detail below in conjunction with the accompanying drawings:

Please refer to Fig. 1, the preferred embodiment of the present invention, a kind of warning method of partial discharge wireless monitoring system, comprises the following steps:

Step S1, reading the partial discharge signal at a certain moment of the equipment under test monitored by the ultrasonic sensor;

Step S2, comparing the partial discharge signal at this moment with the allowable fluctuation range threshold, and judging whether the partial discharge signal at this moment exceeds the allowable fluctuation range threshold;

Step S3, when the partial discharge signal at this moment exceeds the threshold of the allowable fluctuation range, record the moment and count the time, if the duration of the real-time partial discharge signal of the device under test that exceeds the threshold of the allowable fluctuation range detected by the ultrasonic sensor reaches or exceeds the limited time When the threshold is reached, the partial discharge wireless monitoring system generates an alarm message and sends out an alarm signal for the ultrasonic sensor, and then proceeds to step S4; When it is less than the limited time threshold, proceed to step S5;

Step S4, when the real-time partial discharge signal of the device under test detected by the ultrasonic sensor drops and returns to the threshold of the allowable fluctuation range, record the time value and count the time, if the real-time partial discharge signal that returns to the threshold of the allowable fluctuation range lasts When the time exceeds the limited time threshold, record the new time value and end the alarm signal, and store the alarm information in the alarm database; if the duration of the real-time partial discharge signal restored to the allowable fluctuation range threshold is less than the limited time threshold, Then proceed to step S5;

In step S5, the display of the wireless partial discharge monitoring system outputs the real-time partial discharge signal of the device under test, and updates the time when the ultrasonic sensor monitors the real-time partial discharge signal of the device under test, and then proceeds to step S1.

The alarm method of the wireless partial discharge monitoring system of the present invention adopts the principle of a Schmidt trigger, and can issue an alarm for each sensor by comparing and judging real-time monitoring data with a given threshold. When dangerous data appears and its duration exceeds the specified range, the system will give an alarm signal, and make a judgment based on the combination of the limit threshold and the duration, and can adaptively perform alarm and recovery actions.

Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than as a limitation to the present invention, as long as within the scope of the spirit of the present invention, the above-described embodiments Changes and modifications will fall within the scope of the claims of the present invention.

Claims (1)

1. A kind of alarm method of partial discharge wireless monitoring system, is characterized in that, comprises the following steps: Step S1, reading the partial discharge signal of the device under test monitored by the ultrasonic sensor at a certain moment; Step S2, comparing the partial discharge signal at this moment with the allowable fluctuation range threshold, and judging whether the partial discharge signal at this moment exceeds the allowable fluctuation range threshold; Step S3, when the partial discharge signal at this moment exceeds the threshold of the allowable fluctuation range, record the moment and count the time, if the duration of the real-time partial discharge signal of the device under test that exceeds the threshold of the allowable fluctuation range detected by the ultrasonic sensor reaches or exceeds the limited time When the threshold is reached, the partial discharge wireless monitoring system generates an alarm message and sends out an alarm signal for the ultrasonic sensor, and then proceeds to step S4; When it is less than the limited time threshold, proceed to step S5; Step S4, when the real-time partial discharge signal of the device under test detected by the ultrasonic sensor drops and returns to the threshold of the allowable fluctuation range, record the time value and count the time, if the real-time partial discharge signal that returns to the threshold of the allowable fluctuation range lasts When the time exceeds the limited time threshold, record the new time value and end the alarm signal, and store the alarm information in the alarm database; if the duration of the real-time partial discharge signal restored to the allowable fluctuation range threshold is less than the limited time threshold, Then proceed to step S5; In step S5, the display of the wireless partial discharge monitoring system outputs the real-time partial discharge signal of the device under test, and updates the time when the ultrasonic sensor monitors the real-time partial discharge signal of the device under test, and then proceeds to step S1.