"Let me explain the facts!" Fu Xin saw that the two bigwigs were puzzled and applied, and immediately knew what they were going to ask, because he had just said a very unfamiliar term.

"FACTS stands for Flexible AC Transmission System. The English expression of FACTS is: Flexible_Alternative_Current_Transmission_Systems, which is a new technology for flexible and rapid control of AC transmission formed by integrating power electronics technology, microprocessing and microelectronics technology, communication technology and control technology.

This technical concept was first proposed by Dr. N.G. Hingorani of the Electric Power Research Institute (EPRI) NOT LONG AGO, and the specific content is that the application of high-power, high-performance power electronic components to make controllable active or reactive power supply and primary equipment of the power grid can realize the flexible control of the voltage, impedance, phase angle, power, power flow and so on of the transmission system, and the original basically uncontrollable power grid can be fully controlled, so as to greatly improve the flexibility and stability of the power system. The transmission capacity of the existing transmission line is greatly improved.

FACTS technology, that is, technical system application technology and its controller technology, has been identified by some authoritative power workers at home and abroad as "one of the three supporting technologies in the new era of future transmission systems". The three supporting technologies are: flexible transmission technology, advanced control center technology and integrated automation technology.

Flexible AC transmission systems can enhance the stability of AC power grids and reduce the cost of power transmission. This technology improves transmission quality and efficiency by providing induced or reactive power to the grid.

Series Compensation (SC) The series compensation system improves the transmission capacity of the transmission system by improving the stability of the transmission system. Series compensation applications include fixed rate series compensation, thyristor-controlled series compensation TCSC. Thyristor protection series compensation TPSC.

A static var compensator (SVC) is a type of inductive or reactive power compensation that is connected in parallel with the transmission network to achieve dynamic induction. Its main function is to control the voltage quality and reactive power on transmission lines and system nodes.

The innovative SVCPLUS is one of the most economical, space-saving and flexible reactive power compensation systems in a box-type design. It is based on multi-stage circulator technology (VSC). It can improve the reliability and power quality of the transmission system.

Mechanical switching capacitors (MSC/MSCDN) are an effective solution for controlling voltages and stabilizing networks in a steady state. MSCDN with damping network is MSC's upgrade solution that enables high-voltage systems to avoid resonance.

The technical characteristics of the flexible AC transmission system are as follows:

Able to effectively control the power flow in a large range; The conveying capacity of the line can be increased to close to the thermal limit of the wire.

For example. The safe transmission limit of a 500kV line is 1000~2000MW, and the thermal limit of the line is 3000MW, which can increase the transmission capacity by 50%~100% after adopting FACTS technology.

Standby genset capacity can be reduced from the typical 18% to 15% or less; The hazards of power grid and equipment failures can be limited to prevent line tripping to avoid the expansion of accidents; Easy damping eliminates power system oscillation and improves the stability of the system. ”

Gao Wenxin nodded and asked Fu Xin to continue.

"Let's talk about advanced control technology. Advanced control technology refers to the devices and algorithms in the smart grid that analyze, diagnose and predict the state and determine and take appropriate measures to eliminate, mitigate and prevent power supply interruptions and power quality disturbances. These technologies will provide control methods for transmission, distribution, and the user side, and can manage active and reactive power across the grid.

In a way. Advanced control technology closely relies on and serves the other four key technology areas, such as advanced control technology to monitor the parameters of basic components, advanced equipment technology to provide timely and appropriate response, integrated communication technology to provide timely and appropriate response, and advanced decision-making technology to quickly diagnose any event. In addition, advanced control technology supports market quotation technology and improves asset management.

I speculate that in the future, the analysis and diagnosis functions of advanced control technology will introduce a preset expert system, and automatic control actions will be taken within the scope of the expert system.

The actions thus carried out will be at the level of seconds, and this self-healing grid will greatly improve the reliability of the grid. Of course, advanced control technology requires an integrated, high-speed communication system and corresponding communication standards. to process large amounts of data. Advanced control technologies will support distributed intelligent agent software, analysis tools, and other applications.

Advanced control technology has the following characteristics:

First, collect data and monitor grid components.

Advanced control technology evaluates the state of the entire system using system and user parameters measured by smart sensors, smart electronics, and other analytical tools, as well as the status of grid elements, in near real-time. It is of great significance to grasp the overall operation status of the power grid, and at the same time, it is also necessary to use the time signal of the vector measurement unit and the global satellite positioning system to achieve early warning of the power grid.

Second. Analyze the data.

Near-real-time data, along with powerful computer processing power, provides software analysis tools with the ability to scale and advance rapidly.

The state estimation and emergency analysis will be done in seconds rather than minutes, which gives advanced control technology and system operators enough time to respond to urgent problems; The expert system converts data into information for rapid decision-making; Load forecasting will apply this quasi-real-time data along with improved weather forecasting techniques to accurately forecast loads; Probabilistic risk analysis will become routine. Determine the level of risk to the grid during equipment maintenance, during periods of high system stress, and in the event of undesirable power interruptions; Grid modeling and simulation enable operators to understand the exact possible scenarios for the grid.

Third, diagnose and solve the problem.

Quasi-real-time data processed by high-speed computers enables expert diagnostics to determine solutions to existing, developing and potential problems. and submit it to the system operator for judgment.

Fourth, the implementation of automatically controlled actions.

Smart grids make it possible to perform automated control actions for problem detection and response through a combination of real-time communication systems and advanced analytics. It can also reduce the scaling of existing problems and prevent urgent problems from occurring. Modify system settings, status, and power flow to prevent prediction issues from occurring.

Fifth, provide information and options for operators.

Advanced control technology not only provides the control unit with action signals. It also provides information for operators. The large amount of data collected by the control system is not only useful for itself, but also has great application value for the system operators, and these data assist the operators in making decisions. ”

"Finally, there's decision support technology." Fu Xin took a long breath, and then said like a cannon: "Decision support technology is to transform complex power system data into understandable information for system operators at a glance, so animation technology, dynamic coloring technology, virtual reality technology and other data display technologies are used to help system operators understand, analyze and deal with urgent problems."

In many cases, the time it takes for system operators to make decisions has been reduced from hours to minutes or even seconds, so that smart grids require a vast, seamless, real-time application system, tools and training to enable grid operators and managers to make decisions quickly.

Decision support technology needs to meet the following criteria:

First. Visualization. Decision support technology needs to take a large amount of data and cut it into formatted, time period, and the most critical data by technology to grid operators, and visualization technology can display this data in a visual format that operators can quickly grasp for operators to analyze and make decisions.

Second, decision support. Decision support technology needs to identify existing, evolving, and predicted problems, provide decision support analysis, and demonstrate the various scenarios and options that the system operator needs, and the likelihood of success and failure of each option.

Third, dispatcher training. Leverage decision support technology tools and dynamic simulators of industry-certified software to improve the skills and skills of system dispatchers.

Fourth, user decision-making. Demand response (DR) systems can provide users with information in a way that is easy to understand, allowing them to decide how and when to buy, store, or produce electricity.

Fifth. Improve operational efficiency. When decision support technology is integrated with existing asset management processes, managers and users are able to improve the efficiency and effectiveness of grid operation, maintenance, and planning. ”

……

"Comrade Fu Xin, do you know what kind of technical support is needed for the integration of the three networks?" After Fu Xin roughly explained the relevant knowledge of smart grid, Zhou Zhengming returned to the topic. Asked out loud.

Fu Xin nodded and replied: "I know a little bit, triple play needs to include the transmission of SAV messages by sampling values. Object-oriented substation event GOOSE, IEEE1588 clock synchronization protocol and other technical support. ”

"The transmission of sampled values is an important part of the serial communication between the process layer and the spacer layer of the substation automation system. The advent of electronic current/voltage transformers has made it possible to digitally transmit sampled values.

Generic Object-Oriented Substation Events (GOOSE-Generic_Object_Oriented_Substation_Event) is a mechanism used in the IEC61850 standard to meet the needs of fast messages in substation automation systems.

It is mainly used to realize the transfer of information between multiple IEDs, including the transmission of trip and closing signals. It has a high probability of successful transmission. Based on GOOSE network transmission, instead of traditional hard wiring, it realizes the reliable transmission of real-time information such as switch position, latching signal and trip command.

IEEE1588 (Precision_Time_Protocol) is a protocol for time and frequency synchronization of standard Ethernet end devices, abbreviated as 1588, also known as precision clock synchronization protocol PTP.

1588 is divided into two versions: 1588v1 and 1588v2, 1588v1 can only achieve sub-millisecond time synchronization accuracy, while 1588v2 can achieve sub-microsecond synchronization accuracy.

1588v2 is defined as a time synchronization protocol, which was originally only used for high-precision time synchronization between devices, but with the development of technology, 1588v2 also has the function of frequency synchronization. (To be continued......)