Development and application of power system telecontrol devices Abstract: Power system telecontrol devices can provide real-time data for power plants and play a very important role in strengthening information transmission, management and application of power systems. The telecontrol devices in power system are generally summarized, and the operation modes of telecontrol devices are compared. The software telecontrol devices and computerized telecontrol devices in power system telecontrol devices are analyzed, and their application prospects are expounded.
Keywords: electric power system; Remote control device; Electric power monitoring
China Library Classification Number: TD6 1 1 Document Identification Number: A Document Number:1009-2374 (2013) 29-0042-02.
1 summary of telecontrol devices in power system
In the power system, the infrastructure of generator sets, the number distribution of substations and the composition of transmission lines are becoming more and more complicated, so it is necessary to master more safety knowledge to ensure its reliability. In order to obtain more economical and safer power quality, power dispatching needs to accurately and timely grasp the operation state of power system, so it is necessary to take certain information monitoring measures. So as to operate and adjust the data, parameters, working state of the main motor and the input state of the circuit breaker in the operation of the power system. The power system telecontrol device suitable for telecontrol technology far away from dispatching stations and substations can solve this problem, and it can grasp the system information among dispatching stations, power plants and substations in time to complete telecontrol.
The remote control device can complete remote communication, telemetry, remote control and remote adjustment, and transmit information through the remote control channel. Telecontrol channels in power system mainly include multiplexed power line high frequency carrier channel and multiplexed (dedicated) wired channel. The channels of telecontrol devices are usually divided into frequency division system and time division system, and multiplexing method can play the role of channels to a greater extent.
In China's early power system telecontrol devices, most of them were equipped with telemetry data converters and scale conversion display equipment. By using pure hardware logic wiring equipment to monitor the time sequence system at the transmitter, effective time values are provided to ensure the normal work of the power system. With the continuous upgrading of power system automation technology and the continuous progress of computer software technology, the remote control technology of power system has also been improved, and the remote control device is more automatic, integrated and informative.
2 software remote control device
The software telecontrol device has strong flexibility and adaptability, which can not only realize the telemetry and telecommunication of the data related to the power operation system, but also exchange, redistribute and calculate the information value of the system in real time. Correspondingly, the hardware logic wiring device lacks certain information technology, while the software telecontrol device can play a role similar to computer software, and realize the transmission of channel information through software operation.
But there are many differences between it and computer software, the most prominent feature is the instruction system in the software, which can judge instructions through enhanced logic and timely process important information in remote control devices, and has been widely used in power systems. The software telecontrol device has the following obvious characteristics in the use process: in order to make the electric operation instructions more effective, some special marks must be set in the memory to make the device access and processing more accurate. When processing power system information, the telecontrol device needs to exchange and process information with many peripheral devices, such as A/D converter, modem and display and printing equipment, so the convenience of the system and the effectiveness of operation should be fully considered in the instruction setting.
Software telecontrol device plays a very important role in the development and utilization of modern power system engineering with its own telecontrol, automation and power system communication control functions. Its innovative design concept has strong practical value, especially in the following aspects: using software telecontrol device can combine hardware and software of different programs to simulate telecontrol device and simplify various working modes; Effective and accurate real-time calculation; Realize the combination of automation functions of power system stations; Realize the interface function of 1∶N telecontrol device; Various types of communication controllers are used to simulate the telecontrol of power system and realize remote data communication.
3 computer remote control device
Computerized telecontrol device mainly completes remote operation by monitoring and collecting relevant data in power system operation, and its system is usually called SCADA. The computer remote monitoring system is equipped with real-time monitoring equipment at the substation terminal and computer monitoring machine at the dispatching end. RTU is the terminal equipment for remote monitoring of power system, which is mainly composed of microcomputer processor and information interface circuit.
RTU has the characteristics of small volume and strong reliability in the actual working environment of telecontrol device, which can remotely monitor the transformer and unpowered power supply in the power circuit, and remotely measure the voltage of bus and the electric energy of related power supply. Monitoring alarm circuit and circuit breaker; Remotely control the closing of the circuit breaker; Remote monitoring of transformer connection or disconnection. Therefore, SCADA system has many system functions, such as information collection, transmission and processing, and plays an important role in automatic remote control of power system.
The computerized telecontrol device has the following remarkable functions: (1) Information collection function: RTU can collect and monitor the analog quantity, switching quantity and pulse quantity of current and voltage in the power operation system, and then send them to the dispatching terminal by the factory station through the special information channel; (2) Expansion of collection function: SCADA device can collect relevant data and electricity values in power system and record the sequence of events; (3) Information transmission function: adopt the new 1∶N transceiving mode to transmit more power system information for many times; (4) Information processing function: it can compress, circulate and transform different information formats within the communication range; (5) Automation of the connection port between the computer and the power plant; (6) Realize the automatic diagnosis function.
The use of computerized telecontrol devices can play an important role in the collection of data related to power system and the realization of remote control, and can also well combine the local conventional control system and remote control system of power plants and stations in power system. Most modern power systems are equipped with multilevel control systems, so the display status, automation and informatization level of telecontrol devices with different information links in their hierarchical control systems are different, and the corresponding display functions are obviously different. Computerized telecontrol devices can monitor telecontrol devices at different levels and stages, and have their own flexibility and strong adaptability.
Another notable feature of computerized telecontrol device is that it can schedule and monitor the automation level of each stage according to the different needs of users, and establish a certain function division module and bus connection scheme. Users can also adjust according to their own needs to meet different development stages and installation sites, thus improving the adaptability of computerized telecontrol device. One of the development trends of telecontrol devices is to combine multifunctional computers to realize diversified operating systems.
Application prospect analysis of telecontrol device in power system
With the continuous expansion of power system scale and the continuous updating of power production technology, only power telecontrol devices with higher scientific and technological content can make the power system more stable. The purpose of power system telecontrol device is to realize the transmission and exchange of main real-time information and data in power system. The rapid development of computer science, especially microcomputers, poses a higher challenge to telecontrol technology. Only by effectively combining power system with computer science can we obtain more useful data and information resources.
Computer dispatching monitoring remote control system has been widely used in electric power enterprises. For example, in some coal-fired power systems, many pithead power plants have formed unique power generation and distribution systems. The unified management mode of computer networking has improved the overall level of power dispatching and provided practical guarantee for the stable operation of power system. Many types of enterprises have applied computerized scheduling systems to various production departments and managed them in a unified way, which has played an active role in actual remote production.
Usually, the production site is far away from the dispatching center, and the information can be transmitted and controlled more accurately by actively adopting telecontrol technology. By using SCADA, the automatic management process can be accelerated and good results can be achieved. In the process of continuous updating of remote control device technology in power system, the remote control level of power system can be improved by combining relevant computer software technology.
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Power system telecontrol mode 2: research on power system automation telecontrol Abstract With the acceleration of modernization, people's demand for electric energy is increasing, which requires the continuous improvement of power system automation technology. In the process of realizing power system automation, telecontrol technology is essential, so understanding and studying telecontrol technology is a necessary step to strengthen and improve power system automation technology. After briefly introducing the telecontrol technology and principle, this paper expounds the application of telecontrol technology in the process of power system automation.
Power system, automation, telecontrol
The automatic operation of power system is mainly realized by unified communication technology and telecontrol technology, in which the application of telecontrol technology is not only to accurately judge the fault location, but also to effectively analyze the consumption, quality and load of electric energy, so it can be said that telecontrol technology is an important part of realizing the automatic operation of power system.
I. Remote control technology
Telecontrol technology is mainly composed of dispatching, control terminal and execution terminal, which completes remote control, telemetry and other technologies to ensure the stability and reliability of power system operation. Firstly, the relevant data and parameters of the system are collected from the terminal according to the scheduling requirements. After analyzing and judging the running state of the system, the command is fed back to the execution terminal, so as to operate the equipment, adjust the relevant parameters and complete the measurement and control task in real time. It can be seen that the direct information transmission between substation and dispatching and execution terminal is realized by remote control equipment. Its main module has two parts. One is the centralized monitoring module, which is used to monitor the rationality of the system operation under normal circumstances, and if the system fails, it will be handled in time; The other module is the centralized control module, which is used by the staff to realize the remote control and regulation of the power system, which can not only improve the efficiency of the system operation, but also reduce the labor cost.
The basic functions of telecontrol system are telemetry, telecommunication, remote control and remote control. Telemetry is the abbreviation of remote measurement, which refers to the application of communication technology to transmit the measured values of the measured variables. Remote communication, also known as remote communication, uses communication technology to complete the monitoring of equipment status information. Remote control is a command that uses communication technology to change the state of running equipment, also known as remote control command. Remote debugging refers to the remote debugging of remote equipment. The function of telecontrol system is still developing and expanding according to the actual needs of power system. It is necessary to ensure the normal operation of remote equipment and facilitate maintenance.
Second, the principle of telecontrol technology
The general telecontrol process mainly consists of three commands: the generation, sending and receiving of telecontrol information. The transmitter sends information through the telecontrol channel to generate a telecontrol information command, and the receiver executes the command. The main structural difference between telecontrol system and automation system is channel, so the commands transmitted in the channel must be converted by special equipment. Due to this structural factor, the remote control system is vulnerable to external interference, and its operation reliability will be affected. In order to ensure the normal operation of the power system, it is necessary to establish a reliable remote control system, which mainly realizes? Siyao? Function, collecting operation parameters and status information through telemetry and remote communication, and sending them to the dispatching center according to a specific communication protocol. The dispatching center sends commands to the remote terminal to change the operation state and adjust the operation parameters through remote control and telecontrol.
Third, the application of telecontrol technology in power system automation
1, application of data acquisition technology
The equipment running in power system belongs to high voltage and high power equipment. Therefore, it is necessary to convert the operating parameters of these high-voltage and high-power equipment with transmitters, so that the remote control device can process these data and convert them into TTL-level signals, and the analog signals can be converted into digital signals through A/D technology, thus realizing the coding of remote information and the collection of telemetry information. It is necessary to use photoelectric isolation equipment to collect the transmission of remote communication, and write the binary code of the target state in the remote communication data frame and output it to the interface circuit through the digital multiplexer. After the voltage and current signals are collected by current transformer, cathodic protection and sensor, the higher harmonics are filtered by filtering and amplification, and sent to the sample-and-hold link for synchronous acquisition. The signal synchronized with the signal source obtained by A/D conversion is sent to the high-level link to realize data acquisition.
2. Application of channel coding technology
In power system automation, telecontrol channel coding technology mainly involves channel coding and decoding and information transmission protocol. It must be transmitted to the dispatching control center through the channel to use the collected information. Because the channel is susceptible to interference, in order to ensure the anti-interference of information, it is necessary to encode and decode the channel. In power system automation, linear block codes are mainly used for coding and decoding, and cyclic codes are mostly used in linear block codes.
3. Application of communication transmission technology
Modulation and demodulation are two main technologies in power system automation telecontrol communication transmission technology. The power system can use its own power communication network resources to build a special power communication network through various communication modes such as satellite, microwave, optical cable and carrier wave. At present, in the power system automation system, communication and transmission are mainly carried out in the form of power line carrier and optical fiber communication. The data communication of power line carrier is mainly realized by coding in signal transmitter to form baseband signal, using high-frequency harmonic signal on power line as carrier signal, converting baseband signal into analog signal through various modulation techniques, and then communicating with power line in the form of current and voltage. At the same time, at the receiving end, the converted analog signal is restored to digital signal by demodulation technology. Power system automation is to realize data communication of telecontrol system by using modern modulation and demodulation technology.
With the continuous upgrading of optical fiber transmission technology, its reliability is also improving, and the cost of optical channel equipment is also decreasing. Power system automatic control optical fiber transmission network has been formed nationwide, and this new communication transmission network will soon replace the traditional technology and become the mainstream. Power system combines computer technology, communication technology and control technology, and successfully realizes dispatching automation by using its own equipment through telecontrol technology, which improves the construction of power system and thus realizes the automation of power system dispatching.
Conclusion: With the continuous development and improvement of China's scientific and technological level, the scale of power system is expanding and the application of automation system is more extensive. Power system automation combines computer, communication and control technologies, and improves the intelligence and interactivity of the system through telecontrol technology. Moreover, due to the continuous development of computer, communication and control technology, power system automation not only includes the idea of operation management, but also involves the advanced nature and economy of the system. Therefore, we can see that telecontrol technology will become a solid foundation for the development of power system automation after continuous development and improvement.
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