One, foreword
In recent years, in order to reduce the lightning overvoltage of transmission lines in mountainous area caused by the circuit breaker, high voltage transmission line lightning arrester has played a huge role, has been widely used, MOA lightning arrester performance will directly influence the safe operation of power system.Because of MOA arrester long-term in power under the action of a high voltage,will gradually aging, occurrence breakdown may be in operation, protectionproperties decreased, it will have serious consequences, in order to ensure thesafe operation of MOA arrester, must carry on the strict monitoring of MOA surge arrester.

At present, the monitoring of MOA arrester by lightning arrester monitor for on-line monitoring, it works in the operating voltage is normal, the lightning arresterleakage current by the change of current meter measured, when the flow through the action current strong will from the leakage current measurement circuit is transferred to the loop counter, to achieve the record of the number of actionsthe action current energy counter action. However, due to the remoteness of the mountain line, and lightning arrester monitor are installed in the tower height,lightning arrester parameter meter reading and repair work more difficult. The existing methods is the use of regular rotation of arrester, and the tower in theannual standard maintenance inspection, cleaning the lightning arresters and grounding device. The method of lightning arrester high replacement cost, high labor intensity, and the need for power long construction period, is not conducive to the economic and stable operation of the transmission line. Therefore, we must adopt a "online, real-time, remote monitoring, intelligent, reliable" way.

Two, system overview
BLQ-2 MOA transmission line lightning arrester on-line monitoring system(hereinafter referred to as the system), is my company for the requirements of the electric power system and the research and development of high-tech new products. Current detection of this system adopts the single turn core current sensor, sampling mode to realize the full isolation without residual pressure,advanced microprocessor technology and unique transient parameter test technology for the linear processing and calculation, the measurement result ofdigital transmission through the GPRS/GSM: the reliability and security of thesystem with high and low price in this system, which can be fitted to each group of MOA arrester for real-time detection, realize centralized monitoring, can effectively improve the labor intensity of line arrester inspection efficiency, reduce the inspection personnel. Do the accurate and timely grasp the operation of the health status of the equipment, the operating personnel to grasp and deal with the accident hidden danger, ensure the power grid safe power supply.

Three, standards and specifications
DLT5149-2001 220-500kV substation computer monitoring system design technical regulations
Monitor with JB/T10492-2004 AC metal oxide surge arrester
The discharge count JB2440-91 arrester
Q/GDW 393-2009 110 (66) kV ~ 220kV code for design of Intelligent Substation

Four, system characteristics
1 according to the electro [2004]338, "Zinc Oxide arrester on-line monitoring andon-line measurement technology regulations" for the development of.

2 non contact measurement principle: the system’s current detection using non-contact measurement, sampling mode to realize the full isolation without residualpressure, does not have any effect on the lightning arrester, and effectivelyprotect the personal safety and equipment safety.

3 information integrated digital communication: the application of informationsystem integration and digital communication technology, realize the online real time remote function, to realize network management.

4 equipment do not need to change: the installation of the system does not need to remove the installed monitor, can run.

5 outdoor structure, no leakage: current transducer adopts the waterproof design of aluminum alloy shell, is suitable for application of indoor and outdoor.

The 6 alarm threshold: the system for the three level alarm, the user can beoptionally in the detection range value is set, the three level alarm respectively:

Upper primary alarm threshold (I >) 1.1 times the normal current limit

The upper main alarm threshold (I > >) 1.2 times the upper limit of the normal current

The lower limit of the main alarm threshold (I <) 0.9 times the normal current limit

7 effective anti-interference measures: the system made full consideration to interference problems, in the design of hardware and software respectively, using a variety of effective anti-interference processing method, ensure the stability of the system, and the stability of measurement data, can meet the normal use ofperturbation environment demands in strong magnetic field.

8 precision compensation, linear processing: this system adopts the most advanced design methods, the detection signal is linearized, and the precision of compensation, to ensure the accuracy of measurement data.

9 local system uses electric solar power supply, security and stability.

10 based on the wireless data transmission of GPRS/GSM network, the realization of "real-time, online, remote monitoring and intelligent,".

Five, the system main function and technique index

Figure (1) overall system structure diagram

☆ transmission lines MOA arrester current, discharge current detection function,and the current value is sent to the monitoring center through the GPRS/GSMnetwork;

At the same time, the number of full current cumulative action through intelligentSMS transceiver module to the text messages sent to the staff;

☆ MOA transmission line lightning arrester action frequency monitoring function,and through the GPRS/GSM network will be accumulated operating times sent to the monitoring center, at the same time the times accumulative action through intelligent SMS transceiver module in the form of SMS sent to the staff;

(1) the main function and technical requirements

The local system mainly includes two parts of current sensor and a collection box,collecting box comprises a data collector, a solar power supply device and GPRS/GSM wireless data transmission module. Solar power supply deviceprovides the working power supply local system, solar energy allocationaccording to the climate conditions matching. The number of current sensors and real-time measurement of transmission line MOA arrester current, and discharge current action, data is transmitted to the data acquisition and measurement. Data acquisition system has three kinds of working state, the first is to receive the background system sends collection instruction, the number of total current in three-phase current sensor and cumulative action through the GPRS/GSMnetwork to the background; the second is when there is lightning overvoltage,data collector through GPRS /GSM network will be the current and the totalnumber of active action to the background system; third is the normal working state, according to the number of control center set up every day to send to the control center, the automatic transmission the latest test data.

The main technical indicators:

· detect all current range: 0.05 ~ 5.00mA/ RMS error of ± 1% ± 2 characters minimum scale: 10 μ A

· record discharge action cumulative number: 0 ~ 99 correct rate: 100%

The response value · discharge action count: 4/8 μ S ≥ 50A (peak)

· work environment: for outdoor use. -25 ℃ ~ 60 ℃

The detection of the discharge current range: 50A ~ 5kA/ peak error ± 10%minimum scale: 10 A

· power supply: DC5V, safe and reliable, meet the safety of electric power grid requirements.

· work environment: for outdoor use. -40 ℃ ~ 50 ℃

· transmission way: GPRS/GSM network

(2) the main function of the background system

The system includes two parts background software, intelligent SMS transceiver module. Background software installed in the monitoring center server, which can be manually and automatically (can be set every inspection frequency)monitoring data logging each local system, and through the intelligent SMS transceiver module will full current, discharge current, the cumulative action number to text messages sent to the staff on the mobile phone.

The system software is based on Windows platform, the backstage application software system is divided into two parts, monitoring analysis and datamanagement, the system monitoring and analysis part was designed with the object-oriented programming technology, the software has the advantages of simple structure, friendly interface.

Main function:

Data, real-time receiving each local system, display the MOA transmission linearresters, times, users can set the local system every day to send data dischargeclear, can also be data manual inspection of local system;

It has historical data (normal operation data and alarm data) recording function,and can be derived from the generated excel document, edit, print; view real-timecurve, historical curve view.

☆ by SMS module in message mode to full current, the cumulative discharge times sent to the staff on the mobile phone;

The software interface description:

2.1 as shown below, double-click the icon, open system.

Figure 2.2-1 software to open the shortcut icon

2.2 open the software, real-time monitoring interface: 

Real time interface diagram 2.2-2 local system

2.3 history query interface, as shown in the following figure:

The 2.4 alarm records query interface, as shown in the following figure:

Figure 2.2-4 alarm record query interface

2.5 all current curve query interface, as shown in the following figure:

The 2.6 discharge frequency curve query interface, as shown in the following figure: 

2.7 operation menu includes manual inspection, intelligent query and exit system.The following diagram:

Figure 2.2-7 menu operation interface

2.7.1 users can click on the "manual inspection", real-time data acquisition of the local system;

The main function of 2.7.2 "intelligent query" is derived, the historical data,generate a EXCEL table, the user can choose the export content, such as title,terminal, query, test condition, test time, as shown in figure 2.2-7.1, after selection click "confirm", will be based on the selected automatically derived fromhistorical data records of accounts, generate EXCEL table, as shown in figure2.2-7.3, the user can edit, print.

2.7.3 "exit" to exit the system.

Figure 2.2-7.1 intelligent query interface

Figure 2.2-7.2 intelligent query derived record progress

Figure 2.2-7.2 intelligent query form EXCEL export interface

Five, system installation

Installation and debugging system backstage in part by manufacturers to bear,the local system installation in general by the manufacturers to provideinstallation instructions, shall be borne by the buyer line installation personnel.

One, current sensor adopting through type, a lightning arrester through current transmitter can, collecting box is installed without drilling holes in the tower, amounting bracket, see figure.