[in the application of intelligent box substation monitoring based on GPRS network] : summary of 0, with the rapid development of urban modernization in China, urban transformation of power distribution system update, a new type of intelligent box-type substation arises at the historic moment, as shown in figure 1, will the new box-type substation high voltage electricity, step-down transformer, low voltage power distribution, and other functions organically combined together, since it has...
0 overview
With the rapid development of urban modernization in China, urban transformation of power distribution system update, a new type of intelligent box-type substation arises at the historic moment, as shown in figure 1, will the new box-type substation high voltage electricity, step-down transformer, low voltage power distribution, and other functions organically combined together, since it has high degree of integration, factory pre-installed, energy-saving and land-saving, safe, beautiful wait for a characteristic, therefore widely used in the city network construction and retrofit.
Figure 1 smart box substation
With the rapid development of informatization, networking and intellectualization, it is required that the box transformer should not only operate safely and stably, but also have the intelligent function of "four remote" (telemetry, teleconference, teleconference and remote control).
In order to ensure fast and accurate location of fault section, timely fault removal, load belt transfer, network reconstruction and other functions, the power supply can be quickly restored.
However, intelligent box-type substation is generally installed in the load-intensive industrial and mining enterprises, ports, airports, urban public buildings, highways, underground facilities and residential communities and other places;
In order to carry out remote monitoring and system networking for intelligent box-type substation, it is difficult to realize the general fieldbus networking method because of the difficulty in wiring construction.
This paper introduces an application example of intelligent box substation monitoring system based on GPRS network. The system successfully solves the wiring problems existing in the monitoring and control of box substation and realizes the communication problems of remote monitoring system, which has incomparable advantages over the wired communication mode.
At present, the system has been successfully applied in the monitoring of the box substation system of zibo electric power ring network transformation in shandong province.
1. Internal design of remote monitoring system based on GPRS box
The remote monitoring system based on GPRS box transformer adopts the three-layer network structure, as shown in figure 2, namely the field layer, communication layer and management layer.
The field layer is mainly composed of intelligent meters to complete the data collection of electric quantity and non-electric quantity inside the box transformer.
The communication layer is mainly composed of intelligent communication server and GPRS MODEM, which mainly realizes the centralized collection and communication management of field data.
The management does not set up a monitoring center, which is mainly composed of mobile data terminals (user's mobile phone, email, etc.), mainly used for receiving the internal operation data of the box;
The system realizes remote data collection and management by means of mobile GPRS network.
FIG. 2 internal network structure diagram of the system
The intelligent components inside the box transformer are composed of multi-functional network power meter, leakage alarm device, temperature and humidity control device, feeder measuring instrument, switching quantity I/O module, fan fault detection device, intelligent communication server, wireless GPRS MODEM and other intelligent components.
The incoming circuit realizes the measurement of the full electrical parameters on the side of the low-voltage incoming circuit: such as detecting the voltage, current, active power, reactive power, frequency, power factor, four-quadrant electric energy and other electrical parameters of the incoming circuit;
At the same time, it can also realize the remote signal detection of the incoming loop, such as: incoming blade brake, circuit breaker location, circuit breaker fault, etc.
Through its own relay output module, complete the function of remote on-off circuit breaker.
The feeder loop realizes the centralized collection of point parameters of multiple feeder loops through the multi-loop monitoring unit. The current parameters and switch position information of the internal feeder loop are mainly changed by the acquisition box.
Intuitively understand the operation load state and switch position of each feeder line inside the box transformer.
Leakage alarm device by installing in each loop of zero sequence current < a h [in the application of intelligent box substation monitoring based on GPRS network] : summary of 0, with the rapid development of urban modernization in China, urban transformation of power distribution system update, a new type of intelligent box-type substation arises at the historic moment, as shown in figure 1, will the new box-type substation high voltage electricity, step-down transformer, low voltage power distribution, and other functions organically combined together, since it has...
Ref = "http://www.cnelc.com/ProductShop/ShowClass.asp?
ClassId=10907" target="_blank"> transformer collects leakage current of each circuit respectively, and sends an alarm to leakage information exceeding the safety warning;
Improve the power supply safety index of each feeder circuit.
The temperature and humidity controller mainly detects the temperature and humidity inside the transformer transformer and the transformer core temperature.
Through the fan and heater inside the box, adjust the temperature and humidity index inside the box;
Provide stable working environment for internal components of box transformer;
Thus, the service life and safe operation index of internal components can be improved.
The fan fault detection device completes the detection and judgment of the running state of the fan refrigeration fan to improve the index of the safe operating environment of the whole system.
[$page] intelligent communication server is an embedded computer, which has the characteristics of small software code, high automation and fast response speed. It is especially suitable for the system requiring real-time and multi-task.
Embedded system is mainly composed of embedded processor, related supporting hardware, embedded operating system (embedded uCLinux operating system) and application software system. It is a "device" that can work independently.
Support the user programming operation, through the user design application program, to achieve the box internal data acquisition, computing processing, task management, sending information storage and communication with wireless GPRS MODEM functions.
Wireless GPRS MODEM mainly realizes data transmission between intelligent server and wireless public network.
GPRS is a new data service of GSM, which provides a connection between mobile users and data network and provides high-speed wireless IP and x.25 packet data access service for mobile users.
GPRS (General Packet Radio Service) Chinese meaning for the General Packet wireless Service, it is the use of the "Packet Switch" concept developed by a set of wireless transmission mode.
So-called packet switching is to Date encapsulated into many independent packets, then these packets are transmitted one at a time, the form is similar to send packages, use the advantage of packet switching is only when there are data need to transmit to occupy the bandwidth, but also in transport of data quantity, it is a reasonable way of charging for the user, because such as the Internet data transmission bandwidth is idle most of the time.
In addition, in the GSM phase 2+ standard, GPRS can provide four different encoding methods, which also provide different error protection capabilities.
The application of GPRS technology improves the flexibility and stability of communication network.
2. Function analysis of remote monitoring system based on GPRS box
The system functions are designed according to the intelligent requirements of the actual operation of the box transformer and the overall operation cost saving.
The system is mainly composed of two major task modules, namely, operation fault alarm and real-time data acquisition, as shown in figure 3.
Figure 3 system task flow
The operation fault alarm mainly includes the real-time monitoring of the high voltage switch status inside the box transformer and the displacement alarm.
The alarm content is shown in figure 4, including: date and time of fault alarm, station number, circuit name, alarm content and other information;
The alarm range is real-time monitoring of high and low voltage main circuit breaker, fault alarm and displacement alarm;
Real-time monitoring of feeder circuit breaker status and switch shift alarm;
Leakage alarm of each feeder circuit;
Abnormal temperature alarm inside the box;
Fan fault alarm;
And the operation voltage of the phase and unbalanced alarm alarm and other alarm information composition.
The alarm information is mainly collected, calculated and communicated to the intelligent communication server in real time by intelligent components, and then calculated, analyzed and judged by the communication server.
Finally, GPRS modem is used to send the effective alarm information to the designated user's mobile phone through GSM network.
The user responds to the fault alarm in time to shorten the fault recovery time.
At the same time, considering the busy GSM network and whether the user's mobile phone is online and other factors, it supports multiple users to send alarm information at multiple intervals.
Ensure timely transmission of information to users, enhance the security index of system operation.
Figure 4 SMS alarm information
[$page] real-time data monitoring, mainly completed the monitoring of real-time data inside the box transformer.
The contents of the email are shown in figure 5, including: ID number of the sub-station, date and time of sending the email, telemetry on the high and low sides: three-phase voltage, three-phase current, environmental temperature, transformer temperature;
Remote measurement of low-voltage incoming line side: three-phase voltage, three-phase line voltage, three-phase current, active power, reactive power, power factor, frequency, absorption active power, reactive power, load rate, unbalanced rate;
And the three - phase current, leakage current and other information of feeder circuit.
The communication server is responsible for data collection, processing and mail data sending;
In order to ensure the timeliness of alarm data, the acquisition of real-time data is also done on a regular basis. In other words, the communication server is responsible for the collection, processing and storage of data before sending emails.
Then edit the mail to send regular mail, and finally complete the remote sending of real-time data.
Figure 5 content of Email telemetry information
3. Based on the characteristics of GPRS box variable remote monitoring system
Economy;
Because the monitoring stations are relatively scattered, the construction difficulty of cable laying is greatly reduced.
As long as the place covered by GPRS network can complete the monitoring of box substation;
No monitoring master station is set up, and real-time data of the system are sent regularly.
Real-time short message sending of alarm information greatly reduces the cost of data traffic generated by GPRS network;
Reduce the cost of system operation, reduce the system run [in the application of intelligent box substation monitoring based on GPRS network] : summary of 0, with the rapid development of urban modernization in China, urban transformation of power distribution system update, a new type of intelligent box-type substation arises at the historic moment, as shown in figure 1, will the new box-type substation high voltage electricity, step-down transformer, low voltage power distribution, and other functions organically combined together, since it has...
Fees.
Stability and reliability;
This system is completed based on the embedded computer system. Data collection, alarm sending and mail sending are all completed by the embedded computer with a communication server.
Embedded computer embedded uCLinux operating system, has a strong stability and reliability;
Avoid system failure caused by software and hardware, improve the maintainability of system operation.
Independence;
Can operate independently without relying on the inherent monitoring master station;
Each sub-station is an independent monitoring unit, the failure of a single sub-station will not affect the normal use of other sites;
It reduces the malpractice of whole system paralysis caused by single point failure of monitoring main station.
Real-time;
All the functions of the system are completed by the embedded computer, which adopts the uCLinux operating system with high real-time performance. Meanwhile, with the help of the GPRS network with wide coverage, strong coverage signal and fast transmission speed, the real-time performance of data collection, calculation and processing and alarm transmission of the system is greatly improved.
It greatly improves the real time of alarm system and shortens the response time of fault alarm.
Ease of use.
The system completes the configuration of the mobile data receiving terminal through the internal configuration file to facilitate users to change the information of the mobile data receiving terminal;
The main changes completed are: the number of times the SMS alarm is sent, the time interval between sending, the SIM number is received, the email address is sent, the email address is received, the email interval is sent, and the station address is changed;
Users can complete the change of monitoring site information by uploading the changed configuration file to the communication server via FTP upload tool.
Convenient for users to modify and maintain monitoring site information.
4 conclusion
At present, in the communication of intelligent monitoring system of intelligent box substation, digital radio station, GSM short message and optical fiber access are mainly used.
The advantage of digital transmission radio station is that in addition to the annual frequency point fee, there is no additional cost for normal operation. The disadvantage is that it is greatly affected by the terrain and climate, resulting in poor reliability and real-time performance of the system, which cannot be reported actively.
GSM short message mode can achieve active reporting, the disadvantage is by a charge, high running costs, and in the holiday short message center server is busy when the delay is quite long;
Optical fiber communication is stable and reliable, but the construction cost is too large, poor scalability, optical fiber and equipment maintenance is very inconvenient;
GPRS communication avoids the above problems. It has flexible networking, fast data transmission speed and improves the flexibility and stability of data collection.
The practice has proved that the system can not only be used for remote power monitoring, but also has a good application prospect in remote meter reading power management.
reference
1. Shanghai Acrel Co., Ltd
Ren zhicheng zhou zhong. Principles and application guide of digital instrument for electric power measurement. Beijing. China electric power press. 2007.4
3. Xinhua news agency "notice of the state council on the issuance of comprehensive work plan for energy conservation and emission reduction"
4. National development and reform commission "eleventh five-year plan" for energy development. 2007.4
