Converting station electric power equipment outer insulation On-line Monitoring of Leakage Current system
Technical field
The invention belongs to technical field of electricity, relate to converting station electric power equipment outer insulation On-line Monitoring of Leakage Current technology, particularly based on the converting station electric power equipment outer insulation On-line Monitoring of Leakage Current system of virtual instrument technique.
Background technology
Converting station electric power equipment, particularly operate in the converting station electric power equipment in industrial area, coastal and saline and alkaline area, the electric current that the surface filth laminar flow is crossed is subjected to voltage, filth, weather three elements combined influence, when the insulating surface pollution level is serious, at any time the pollution flashover accident can take place.Pollution flashover not only constitutes a serious threat to electric power netting safe running, and will cause enormous economic loss.The present invention is by having reviewed and analysed the present situation and the prior art of UHV (ultra-high voltage) transformer station many equipment outer insulations On-line Monitoring of Leakage Current, successfully propose and developed this external insulation leakage current monitoring system, at the electric system hanging net operation, significant to improving the power equipment operational reliability.
As the Chinese patent (patent No.: ZL01115300.8) a kind of dirt sparkle of transformer station on-line monitoring system and method, Chinese patent (the patent No.: ZL90205395.7) filthy leakage current automonitor, the Chinese patent (patent No.: ZL93207372.7) the filthy electric current automatic monitoring warning of circuit device etc.Now the domestic and international product of developing some be based on the detection of single device, some are monitoring systems of line insulator, and to the monitoring system of the many equipment outer insulations of transformer station seldom.Though these products have many advantages, also there is weak point separately in they.They are many based on embedded microprocessor technically, owing to be subjected to the restriction of processor bus speed and storage capacity, be difficult to unification most power equipment external insulation in the transformer station is monitored; Most of system adopts single-chip microcomputer to do slave computer to solve the transmission of data with host computer communication, and the software aspect all is a stand-alone development, and is portable poor.
Along with development of computer, by software platform and hardware integrated circuit board, adopt the mode bus that is fit to again, the virtual instrument of formation has obtained application more and more widely.It controls bottom hardware with virtual control, and the collection, analyzing and processing and the result that are finished signal by powerful software show, have realized the theory of " software is exactly instrument ".The monitoring system that adopts this thought to make up also possesses numerous advantages of virtual instrument, so this technology has more characteristics such as efficient, easy-to-use, flexible, powerful.At present, the extensive popularization of virtual instrument technique uses general data collecting card and special programming software can save a lot of man power and materials' input, shortens product development cycle, and can develop the product of superior performance.
Adopt the method for artificial intelligence to predict that the variation tendency of leakage current and the method for insulation pollution level development trend do not use at related system as yet in addition, and these prediction work have considerable meaning, and it does necessary place mat work for the repair based on condition of component of power system device and assessment and diagnosis.According to the concrete condition of China transformer station, concentrate monitoring and develop advanced diagnosis and forecasting software significant to the external insulation leakage current of multiple devices in the transformer station.
Summary of the invention
In order better to realize the accurate measurement of transformer station's major equipment leakage current, and provide the prediction of more real field monitoring data and state of insulation for electric system, the change scheduled overhaul is repair based on condition of component, the objective of the invention is to, the transformer station's many equipment multiple spot external insulation On-line Monitoring of Leakage Current Study on Technology based on virtual instrument technique is carried out in proposition, and develops corresponding monitoring system on this basis.
Fundamental purpose of the present invention comprises following content:
(1) seeks to be suitable for the method for sensing that various power equipment external insulation leakage currents are monitored;
(2) develop signal condition, signal transmission and the data acquisition circuit that is used for faint leakage current, and on-the-spot Anti-Jamming Technique measure is applied to the design of these circuit;
(3) exploitation realizes functions such as circulatory monitoring, numerical evaluation, historical query, trend prediction, fault alarm, demonstration printing, remote monitoring based on virtual instrument technique and graphical programming language monitoring system software;
The technical solution that realizes the foregoing invention purpose is that a kind of On-line Monitoring of Leakage Current system based on virtual instrument technique is characterized in, comprises with the lower part:
1) gets flow sensor a
Getting flow sensor a is used to extract operating external insulation leakage current and realizes the high-low pressure electrical isolation; Get stream ring and small current mutual inductor electrical isolation unit comprising a stainless steel scalable that is arranged on the support insulator, scalable is got the primary coil N of stream ring and small current mutual inductor electrical isolation unit
1Connect secondary coil N
2Be used for induction of signal output;
2) front end signal conditioning unit b
Front end signal conditioning unit b is a module, is used for the conditioning to faint leakage current signal; Comprising multi-strobe circuit, variable-gain amplification circuit, low-pass filter circuit and voltage-current converter circuit;
3) back end signal conditioning unit c
Back end signal conditioning unit c is similarly a module, be used for the electrorheological feed signals that each on-the-spot leakage current conditioning unit conditioning obtains, after realizing anti-interference filtration, electrical isolation by this unit after the long Distance Transmission, nurse one's health into the scope that the data collecting plate card analog input channel allows, comprising multi-strobe circuit, isolate before low-pass filter circuit, analog linearity buffer circuit and isolate the back low-pass filter circuit;
4) industrial computer
Be used for data acquisition, analysis, calculating that monitoring of software driving data capture card follows inspection in the industrial computer, specifically finish and follow inspection, storage, demonstration, warning, inquiry, prediction, print;
Comprise data acquisition unit d, data analysis unit e and trend prediction unit f in the industrial computer;
Data acquisition unit d is used for the measurement of on-the-spot many equipment multiple spot leakage current values and ambient temperature and humidity parameter under the control of monitoring of software, comprises a multifunctional data acquisition card PCI-6025 and digital I/O control card PCI-6503;
Data analysis unit e is used for the Butterworth low pass iir digital filter of leakage current and contains the small echo noise-removed technology of analyzing based on the wavelet multiresolution rate, calculates the leakage current effective value, and carries out the early warning of firsts and seconds setting valve and judge;
Trend prediction unit f is used to take all factors into consideration leakage current values and ambient temperature and humidity parameter, trend prediction software and ambient temperature and humidity are measured hardware cell, by LabVIEW software transfer Matlab, by the BP neural network prediction algorithm of software set, realize the leakage current numerical prediction in 12 hours futures and 24 hours.
The sensing that the present invention has systematically studied the external insulation leakage current is got the extraction and the technology such as transmission technology, hardware filtering technology, shield technology and photoelectricity isolation of stream technology, high-low pressure electrical isolation technology, feeble signal, and the leakage current of having developed the power equipment external insulation that is suitable for the different structure size is got flow sensor, isolated hardware such as amplifying unit, signal condition unit, front and back end, data acquisition unit.Isolate amplifying unit and realized the insulation blocking that high-low pressure is electric, wherein the measuring accuracy of current transformer can reach 1 μ A and measurement range be 1 μ A to 2A, system has higher measuring accuracy and stability.The current signal transmission of 4-20mA, functions such as the gating control of the control of variable gain and many monitoring points have been realized in signal condition unit, front and back end.Adopted the Butterworth low-pass filter circuit, transient voltage suppression circuit, three cover electric supply systems, optocouplers etc. have solved on-the-spot anti-interference problem.
The present invention utilizes virtual instrument technique, database technology, software filtering technology and trend prediction technology, developed monitoring of software based on graphical programming language LabVIEW and data base management system (DBMS) SQL SERVER 2000, the monitoring and the Control Software such as cycle detection, data analysis, data processing, trend prediction, remote monitoring of the many equipment leakage currents of transformer station have been developed, developed digital filter software submodules, developed leakage current variation tendency forecasting software submodule based on neural network based on IIR and the analysis of wavelet multiresolution rate.On-the-spot operation shows that the software of exploitation has stable, friendly interface, the characteristics that function is complete.Monitoring is good with control function, and digital filtering module has been realized the inhibition of high-frequency interferencing signal and the extraction of power frequency useful signal, and forecasting software has been realized preliminary leakage current variation tendency prediction.
Description of drawings
Fig. 1 is a system functional block diagram of the present invention.
Fig. 2 is that leakage current is got the stream schematic diagram.Wherein a gets the flow structure synoptic diagram, and b gets the current circuit schematic diagram.
Fig. 3 is a front end signal conditioning Elementary Function block diagram.
Fig. 4 is a back end signal conditioning Elementary Function block diagram.
Fig. 5 is a temperature and humidity measurement Elementary Function block diagram.
Fig. 6 is leakage current monitoring of software master interface.
Fig. 7 is the monitoring facilities process flow diagram.
Fig. 8 is the forecast function process flow diagram.
Embodiment
The present invention is described in further detail below in conjunction with embodiment that accompanying drawing and inventor provide.
The outdoor insulative of converting station electric power equipment comprise the insulator of line insulation, power station supports insulative and electrical equipment and sleeve pipe etc. along face or air insulation etc., should choose different monitoring schemes as the case may be to dissimilar outdoor insulatives.In the on-line monitoring such as line insulator, often adopt embedded pc system and wireless communication technique to solve the transmission problem of data, monitoring system is installed on the line steel tower nearby, is managed and monitored and finish concentratedly the storage and the analysis of Monitoring Data by the Surveillance center in a distant place.And, have following power equipment in standing usually: current transformer, voltage transformer (VT), transformer, lightning arrester, isolating switch and disconnector for transformer station.The actual conditions big according to the outdoor substation floor area, that equipment disperses, the present invention has designed a centralized monitoring system.This system is mainly by forming with the lower part:
1) gets flow sensor a
Getting flow sensor a is used to extract operating external insulation leakage current and realizes the high-low pressure electrical isolation; Get stream ring 1 and small current mutual inductor electrical isolation unit 2 comprising a stainless steel scalable that is arranged on the support insulator, scalable is got the primary coil N of stream ring 1 and small current mutual inductor electrical isolation unit 2
1Connect secondary coil N
2Be used for induction of signal output;
2) front end signal conditioning unit b
Front end signal conditioning unit b is a module, and functional block diagram as shown in Figure 3.Be used for conditioning to faint leakage current signal; Comprising multi-strobe circuit 3, variable-gain amplification circuit 4, low-pass filter circuit 5 and voltage-current converter circuit 6, this module allows the input of 3 road or 6 road analog voltage signals, have 1 *, 10 *, 100 *, 1000 * four amplify gears, the low-pass cut-off frequencies of low-pass filter circuit 5 is 1kHz, and voltage-current converter circuit 6 realizes that the electrorheological of 4mA~20mA send;
3) back end signal conditioning unit c
Back end signal conditioning unit c is similarly a module, and functional block diagram as shown in Figure 4.Be used for the electrorheological feed signals that each on-the-spot leakage current conditioning unit conditioning obtains, after realizing anti-interference filtration, electrical isolation by this unit after the long Distance Transmission, nurse one's health into the scope that the data collecting plate card analog input channel allows, comprising multi-strobe circuit 7, isolate before low-pass filter circuit 8, analog linearity buffer circuit 9 and isolate back low-pass filter circuit 10;
4) industrial computer
Follow data acquisition, analysis, the calculating of inspection in the industrial computer with monitoring of software driving data capture card, specifically finish and follow inspection, storage, demonstration, warning, inquiry, prediction, print;
Comprise data acquisition unit d, data analysis unit e and trend prediction unit f in the industrial computer;
Data acquisition unit d is used for the measurement of on-the-spot many equipment multiple spot leakage current values and ambient temperature and humidity parameter under the control of monitoring of software, comprises a multifunctional data acquisition card PCI-6025 and digital I/O control card PCI-6503;
Data analysis unit e is used for the Butterworth low pass iir digital filter of leakage current and contains the small echo noise-removed technology of analyzing based on the wavelet multiresolution rate, calculates the leakage current effective value, and carries out the early warning of firsts and seconds setting valve and judge;
Trend prediction unit f is used to take all factors into consideration leakage current values and ambient temperature and humidity parameter, develop trend prediction software and ambient temperature and humidity and measured hardware cell, by LabVIEW software transfer Matlab, by the BP neural network prediction algorithm of software set, realize the leakage current numerical prediction in 12 hours futures and 24 hours.
The whole system operation flow process is; employing is installed on the power equipment external insulation sleeve of full station near the stream device of getting of ground connection flange position and obtains leakage current signal to be monitored; pass through protected location and current sensor then; compile near the conditioning of the advance signal power equipment unit in arriving at a station; simulating signal after the conditioning is aggregated into conditioning unit, rear end through long-distance transmissions; and then follow the data acquisition of inspection by industrial personal computer monitoring software-driven data collecting card; analysis software has been realized inquiry; data analysis and processing; trend prediction, functions such as remote monitoring.System functional block diagram as shown in Figure 1.
The getting in the stream device of leakage current among Fig. 2 got stream ring 1 usefulness is wide and make for the stainless steel band of 5mm, and it has from fastening function.Scribble conducting resinl at stainless steel band with the contacted side of porcelain vase external insulation, it is firmly connected and excellent conducting performance is arranged.
In the current transformer electricity isolation device among Fig. 2, adopt permalloy as permeability magnetic material, employing be the punching winding method, secondary is electric current output.Single unit system is realized water-proof function with silicon rubber cast encapsulation.
Realized the conditioning functions of variable gain in the front end signal conditioning unit among Fig. 3, four adjustable gears have been arranged.The electrorheological of having realized 4mA~20mA send.
Accept the control signal of control module in the back end signal conditioning unit among Fig. 4, realize the electrical isolation function of field unit and measuring unit.
Humiture unit among Fig. 5 adopts the temperature sensor AD 590 of AD company and the humidity sensor HIH3062L of Honeywell company.The electrorheological of having realized 4~20mA is sent here and is transmitted the humiture parameter.The calculations incorporated of relative humidity the measurement data of temperature, converse actual rh value.
Fig. 6 is the On-line Monitoring of Leakage Current system software master interface based on the virtual instrument technique exploitation.Realize the purpose of on-line monitoring based on the thought of traditional instrument measurement.Software can be set manually and full-automatic two kinds of monitoring patterns.
Fig. 7 is the monitoring function process flow diagram.The software of this monitoring system has been set two kinds of monitoring patterns (manually with automatic), and under the hardware of back end signal conditioning unit and front end signal conditioning unit cooperates, has realized the measurement to scene monitoring of equipment point leakage current signal to be monitored.Signal after the conditioning enters the analog input channel of data collecting card, realize analog to digital conversion by the software control integrated circuit board, digital filter program and the various undesired signals of wavelet analysis technology filtering, the effective value calculation procedure calculates the effective value of leakage current, judge its state of insulation according to two-stage Threshold Alerts setting valve, and together deposit the additional information of this signal in database.Software has also been realized pilot lamp alarm indication of main interface and audible alarm etc.
Fig. 8 is the forecast function process flow diagram.Forecast function is divided into single step prediction and multi-step prediction.The single step predictive mode is input as 24 of the monitoring equipments average leakage current data per hour in some 24 hour time period, 24 average ambient temperature data per hour, and 24 average environment humidity datas per hour are output as the predicted data of 1 time period.The multi-step prediction pattern, import constant, still be 24 of the monitoring equipments average leakage current data per hour in some 24 hour time period, 24 average ambient temperature data per hour, 24 average environment humidity datas per hour are output as 12 hours each corresponding period average leakage current predicted data in the future.
The comprehensive on-line monitoring system of converting station electric power equipment outer insulation that the applicant makes according to technique scheme, hanging net operation in the 110kV transformer station of Xie village, tafelberg.Hanging net operation is the result show, the present invention can be adapted at installing and using on transformer station's distinct device.The leakage current data of converting station electric power equipment under normal weather operation is: PT external insulation leakage current variation range 90 μ A~200 μ A, CT external insulation leakage current variation range 60 μ A~100 μ A, isolating switch external insulation leakage current variation range 20 μ A~60 μ A, transformer 110kV side sleeve pipe external insulation leakage current variation range 20 μ A~40 μ A, transformer 35kV side sleeve pipe external insulation leakage current variation range 160 μ A~200 μ A.And long-term historical trend curve map show this invention can reliably monitor effectively leakage current in time, the Changing Pattern of temperature and humidity, system works is stable, has obtained good effect.