CN101718813A - Method for monitoring voltage acquisition circuit of electric power secondary system - Google Patents

Abstract

The invention relates to a method for monitoring a voltage acquisition circuit of an electric power secondary system. The method comprises the following steps of: collecting the electrical quantity acquired by each relay protection device on one bus and the abnormal TV-circuit detecting result of each relay protection device by using a monitoring center, judging whether the voltage acquisition circuit corresponding to each relay protection device is abnormal after comprehensive comparison, and accurately positioning the abnormity at the voltage circuit of the corresponding phase of the corresponding relay protection device, thereby accurately reflecting the state of the voltage acquisition circuit, realizing the state monitoring of the voltage circuit, greatly reducing the workload for overhauling and trouble shooting, shortening the outage time for equipment overhauling and improving the work efficiency.

Description

Monitoring Method of Voltage Acquisition Circuit in Power Secondary System

technical field

The invention relates to a state monitoring technology of a power secondary system, in particular to a monitoring method for a voltage acquisition circuit of a power secondary system.

Background technique

The power relay protection system consists of various links such as the AC circuit, the DC circuit, the relay protection device itself, and the tripping and closing circuit of the circuit breaker. The maintenance of relay protection is still in the stage of preventive maintenance, and the mode of regular maintenance is adopted during operation. Regular maintenance does play a role in directly preventing or delaying failures in ensuring the normal operation of the equipment, but this kind of maintenance that is not based on the actual condition of the equipment, but simply at regular intervals, will inevitably lead to redundant maintenance, which will not only cause the equipment to use time effectively. Loss and waste of manpower, material and financial resources, and even cause maintenance failures. The most ideal mode is condition-based maintenance, based on the status response of the equipment, through the continuous observation of the equipment and other factors, identifying the existing or ongoing or potential performance degradation of the equipment, and making a reasonable assessment of the equipment status , to determine the best time to overhaul the equipment. Condition-based maintenance must be based on effective monitoring of equipment status.

The AC sampling loop of the relay protection device is very important, which directly affects the action behavior of the protection. In order to realize condition-based maintenance, effective online monitoring of the voltage sampling loop must be carried out. With the development of software and hardware technology, platform technology has been gradually applied in the design and manufacture of relay protection, so that the application scope of protection can be appropriately expanded to circuits other than devices, which provides a basis for expanding the online monitoring of related circuits in the protection system. possible.

For the monitoring of the voltage circuit, it is mainly implemented in the relay protection device at present. By detecting the zero-sequence voltage and the absence of zero-sequence and negative-sequence current when the relay protection device samples the zero-sequence voltage, it can be judged that the single-phase or two-phase voltage is lost; by detecting the three-phase voltage The change of current before and after the loss is close to zero to judge the three-phase voltage loss under normal load conditions; through the current detector to detect the current change before and after charging and the three-phase voltage value to comprehensively judge the loss of the three-phase voltage when the line is charging. This method only realizes the alarm function after the secondary circuit is abnormal, and the abnormal location is not accurate enough. When troubleshooting the abnormality, it is necessary to check the voltage secondary circuit and the AC acquisition circuit of the relay protection device in an interval, and the workload is heavy.

Contents of the invention

The purpose of the present invention is to provide a method for monitoring the voltage acquisition circuit of a power secondary system to determine whether there is an abnormality in the voltage acquisition circuit and accurately locate the abnormality of the secondary circuit corresponding to the phase voltage.

In order to achieve the above purpose, the technical solution adopted is: a method for monitoring the voltage acquisition circuit of a power secondary system, comprising the following steps:

(1) More than one relay protection device on a bus samples electrical quantities such as the three-phase voltage of the system and the three-phase current of the corresponding relay protection device;

(2) Each relay protection device detects whether the TV circuit is abnormal according to the collected electrical quantity; each relay protection device detects whether the TV circuit is abnormal according to the collected electrical quantity, and each relay protection device has no TV circuit abnormal signal. Send sampling data to the monitoring center in a fixed-frequency cycle, and execute step (3); when any relay protection device detects an abnormal signal of the TV loop, immediately send a corresponding TV loop abnormal alarm signal to the monitoring center, and execute step (5);

(3) Calculate the average value of the corresponding phase voltage of each relay protection device;

(4) The monitoring center separately calculates the absolute value of the difference between each phase voltage of each relay protection device and the average value of the corresponding phase voltage. If the calculated absolute value of the difference is greater than the set preset value, it will send the corresponding voltage acquisition Circuit abnormal alarm signal;

(5) According to the abnormal alarm signal of the TV circuit and the abnormal alarm signal of the voltage acquisition circuit, the abnormal circuit is located.

The method for locating the abnormal circuit described in step (5) is: if there is an abnormal alarm signal of the TV circuit, the monitoring center directly prompts that the corresponding TV circuit is abnormal; otherwise, further judge the phase voltage and the corresponding phase voltage average value of each relay protection device If the absolute value of the calculated difference is greater than the set preset value, it can be determined that the corresponding phase voltage acquisition circuit of the corresponding relay protection device is abnormal.

The calculation method of the average value of the corresponding phase voltage of each relay protection device described in step (3) is: the sum of the corresponding phase voltage values sampled by each relay protection device is divided by the total number of relay protection devices.

The detection method of detecting whether the TV circuit is abnormal in real time based on the collected electrical quantity at the relay protection device end is: by detecting that there is no zero-sequence and negative-sequence current when there is zero-sequence voltage sampled by the relay protection device, it is judged that the single-phase or two-phase voltage is lost; Three-phase voltage loss under normal load conditions can be judged by detecting that the current variation before and after the three-phase voltage loss is close to zero; through the current detector to detect the current change before and after charging and the three-phase voltage value to comprehensively judge the three-phase voltage loss when the line is charging.

The sampled electrical quantities of each relay protection device and the abnormal alarm signal of the TV circuit are sent to the monitoring center in the form of telemetry values.

The present invention adopts the monitoring center to collect the electrical quantity collected by each relay protection device on a bus and the TV circuit abnormality detection results of each relay protection device, and judges the corresponding voltage collection circuit of each relay protection device after comprehensive comparison Whether there is an abnormality, and accurately locate the abnormality to the corresponding phase voltage circuit of the corresponding relay protection device, realize the accurate positioning of the abnormality of the voltage acquisition circuit, greatly reduce the workload of maintenance and troubleshooting, reduce the maintenance and power outage time of the equipment, and improve the work efficiency. efficiency.

Description of drawings

Fig. 1 is a flow chart of the method for monitoring the voltage acquisition circuit of the electric power secondary system of the present invention.

Detailed ways

The voltage acquisition loop monitoring system used in this embodiment is composed of multiple relay protection devices with multiple electrical intervals on one bus, and a monitoring center. Each relay protection device collects the bus voltage value, and transmits the voltage collection value to the monitoring center, and the monitoring center comprehensively judges whether there is any abnormality in the voltage collection circuit, and if there is an abnormality, locates the voltage circuit of a certain phase at a certain interval.

The relay protection device itself has the function of TV circuit abnormality detection, and the detection result is sent to the monitoring center as the judgment condition when abnormality is located.

As shown in Figure 1, the method for monitoring the voltage acquisition loop of the power secondary system in this embodiment includes the following steps:

(1) More than one relay protection device on a bus samples electrical quantities such as the three-phase voltage of the system and the three-phase current of the corresponding relay protection device;

(2) Each relay protection device detects whether the TV circuit is abnormal according to the collected electrical quantity. The method is: by detecting the zero-sequence voltage sampled by the relay protection device, there is no zero-sequence and negative-sequence current, and distinguishing single-phase or two-phase voltage Loss; judge the three-phase voltage loss under normal load conditions by detecting that the current change before and after the three-phase voltage loss is close to zero; use the current detector to detect the current change before and after charging and the three-phase voltage value to comprehensively judge the three-phase voltage loss when the line is charging ; When each relay protection device has no TV loop abnormal signal, it sends sampling data to the monitoring center according to a fixed frequency cycle, and performs step (3); when any relay protection device detects a TV loop abnormal signal, it immediately sends a corresponding signal to the monitoring center abnormal alarm signal of the TV loop, perform step (5);

(3) Calculate the average value of the corresponding phase voltage of each relay protection device. The calculation method is: the sum of the corresponding phase voltage values sampled by each relay protection device is divided by the total number of relay protection devices. ;

(4) The monitoring center separately calculates the absolute value of the difference between each phase voltage of each relay protection device and the average value of the corresponding phase voltage. If the calculated absolute value of the difference is greater than the set preset value, it will send the corresponding voltage acquisition Circuit abnormal alarm signal;

(5) According to the abnormal alarm signal of the TV loop and the abnormal alarm signal of the voltage acquisition loop, locate the abnormal circuit. The method is: if there is an abnormal alarm signal of the TV loop, the monitoring center will directly prompt the abnormality of the corresponding TV loop; The absolute value of the difference between each phase voltage of the protection device and the average value of the corresponding phase voltage. If the absolute value of the calculated difference is greater than the set preset value, it can be determined as the corresponding phase voltage acquisition circuit of the corresponding relay protection device. If abnormal, prompt the operation and maintenance personnel to overhaul the voltage acquisition circuit of the corresponding relay protection device.

The sampled electrical quantities of each relay protection device and the abnormal alarm signal of the TV circuit are sent to the monitoring center in the form of telemetry values.

For unattended substations in remote areas, the monitoring center can be in a remote place, and the electrical quantities collected by the relay protection device and the abnormal detection results of the TV circuit are sent to the remote relay protection monitoring center through the telecontrol protocol to realize remote status monitoring.

Claims (5)

1. a method for monitoring voltage acquisition circuit of electric power secondary system is characterized in that, this method step is as follows:

Article (1) one, more than one protective relaying device is sampled to the electrical equipment amounts such as three-phase current of system's three-phase voltage and corresponding protective relaying device on the bus;

(2) whether each protective relaying device to detect the TV loop according to institute's electric parameters of gathering respectively unusual, circulates to Surveillance center's transmission sampled data, execution in step (3) according to fixed frequency when each protective relaying device all has TV loop abnormal signal; When arbitrary protective relaying device detects TV loop abnormal signal, send corresponding TV loop abnormal alarm signal, execution in step (5) to Surveillance center immediately;

(3) calculate the mean value of the corresponding phase voltage of each protective relaying device;

(4) Surveillance center calculates the absolute value of each phase voltage with the difference of corresponding phase voltage mean value of each protective relaying device respectively, if the absolute value of the difference of being calculated promptly sends relevant voltage acquisition circuit abnormal alarm signal greater than setting preset value;

(5) according to TV loop abnormal alarm signal and voltage acquisition circuit abnormal alarm signal, unusual circuit is positioned.

2. method for monitoring voltage acquisition circuit of electric power secondary system as claimed in claim 1 is characterized in that, the method for the unusual circuit in location described in the step (5) is: if exist TV loop abnormality alarming signal, Surveillance center directly to point out corresponding TV loop unusual; Otherwise further judge the absolute value of each phase voltage with the difference of corresponding phase voltage mean value of each protective relaying device, unusual if the absolute value of the difference of being calculated, can be decided to be the corresponding phase voltage acquisition circuit of corresponding protective relaying device greater than setting preset value.

3. claim 1 or 2 described method for monitoring voltage acquisition circuit of electric power secondary system; it is characterized in that the computing method of the mean value of the corresponding phase voltage of each protective relaying device described in the step (3) are: the corresponding phase voltage value sum of each protective relaying device sampling is divided by the total number of protective relaying device.

4. method for monitoring voltage acquisition circuit of electric power secondary system as claimed in claim 3, it is characterized in that, the protective relaying device end detects the TV loop in real time according to the collection electric parameters, and whether unusual detection method is: do not have zero sequence and negative-sequence current by detecting when the protective relaying device sampling has residual voltage, differentiate single-phase or two phase voltages are lost; The variable quantity of losing the front and back electric current by the detection three-phase voltage approaches the zero three-phase pressure loss under the normal load situation of differentiating; Three-phase voltage is lost when comprehensively judging line charging by current sensor detection charging front and back electric current variation and three-phase voltage value.

5. method for monitoring voltage acquisition circuit of electric power secondary system as claimed in claim 4 is characterized in that, the sampling electric parameters of each protective relaying device and TV loop abnormality alarming signal are sent to Surveillance center in the mode of remote measurement value.

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