Multi energy complementary system
Multi energy complementary system is the extension of traditional distributed energy application, and the embodiment of integrated concept in the field of energy system engineering, which makes the application of distributed energy expand from point to area, from local to system. Specifically, the multi energy complementary distributed energy system refers to a "regional energy Internet" system that can contain multiple energy resource inputs and has multiple output functions and transport forms. It is not a simple superposition of many kinds of energy, but a comprehensive and complementary utilization should be carried out at the system level according to different energy grades, and the coordination relationship and conversion between various kinds of energy should be arranged as a whole to achieve the most reasonable energy utilization effect and benefit.
brief introduction
編輯Significance
編輯There are two modes for the demonstration project of multi energy complementary integrated optimization: one is to meet the end-user's demand for electricity, heat, cold, gas and other kinds of energy, to adjust measures to local conditions, develop as a whole, make complementary use of traditional energy and new energy, optimize the layout and build an integrated energy supply infrastructure, and realize the project by means of natural gas combined heat, power and cooling, distributed renewable energy and energy intelligent micro network At present, multi energy collaborative supply and energy comprehensive cascade utilization are available; second, the construction and operation of wind, solar, water, coal, natural gas and other resources combination advantages of large-scale comprehensive energy base are utilized to promote the construction and operation of wind, water and fire storage multi energy complementary system.
The construction of the multi energy complementary integrated optimization demonstration project is one of the important tasks of building the "Internet plus" smart energy system, which is conducive to improving the coordination of energy supply and demand, promoting clean energy production and consumption, reducing the wind power, abandoning light, abandoning water power and promoting renewable energy consumption. It is an important starting point for improving the comprehensive efficiency of energy system, and for building clean, low carbon and high safety. The efficiency of modern energy system has important practical and far-reaching strategic significance.
[1]Main functions of multi energy complementary system
編輯(1) Multi energy flow SCADA
It is used to realize complete and high-performance quasi steady-state real-time data acquisition and monitoring functions, which is the basis of the follow-up early warning, optimization and control functions, and uses the services provided by the system software support platform. Multi energy flow SCADA is the "sensory system" of I multi energy complementary system. Based on the energy Internet of things, it collects multi energy flow data (sampling frequency: second level for electricity, second level for hot / cold / gas), completes the corresponding monitoring function, and provides the data to the state estimation and subsequent high-level application function modules, receives the system operation control instructions, and sends them to the system through remote control / remote adjustment signals Unified equipment implementation. The function interface of multi energy flow SCADA includes energy flow distribution, station wiring, system function, comprehensive monitoring, operation information, analysis and evaluation, intelligent alarm, etc.
(2) State estimation of multi energy flow
Because of the wide distribution of measurement points, many kinds of measurement, low data quality, difficult maintenance and high cost sensitivity, it is inevitable that the data collected is incomplete and wrong. Therefore, the multi energy flow network needs state estimation technology to provide real-time, reliable, consistent and complete network state, which provides the basis for IEMs evaluation and decision-making. Multi energy flow state estimation can realize the Estimability, detectability and identifiability of bad data by complementing measurement data and eliminating bad data. Finally, it can reduce the number of sensors installed, the complexity of communication network, the investment and maintenance cost of sensor network, improve the reliability of evaluation and decision-making and reduce the energy network by improving the reliability of basic data Operation accident risk.[2]
(3) Safety assessment and control of multi energy flow
The importance of safety is self-evident, and the safety of energy system is especially related to the safety of life and property. On the one hand, it is necessary to establish the concept of "n-1" safety criterion, which is to pay attention to the weakest link and make a plan. In the morning, we gave an example at our achievement conference, which said that a recent blackout in Taiwan was caused by the failure of a gas valve, so that valve is a weak link of the gas electricity coupling integrated energy system. Therefore, we must always pay attention to the weak links and have plans for problems, or we will face huge risks. On the other hand, we should pay attention to the safety control of the trade gateway in the park. The capacity configuration and operation cost of the gateway in the park is a key issue. On the one hand, the larger the capacity is, the higher the investment cost of the transformer is, and on the other hand, the higher the capacity fee charged by the grid company is. For example, the total cost of investment and operation of 50MW capacity and 100MW capacity is quite different. If the capacity is designed as 50MW capacity, in case the actual capacity exceeds, the transformer will be burned. How to control the power flow at the gate within 50MW is the problem of safety control. In the multi-energy flow system, different energy systems are coupled and affected by each other. The fault and disturbance of one part will affect the other parts of the multi-energy flow system, which may cause chain reaction. Therefore, coupling analysis is needed. It can make use of the flexibility provided by the inertia of heat, gas and other systems to provide new methods for the safety control of electrical systems. It can make use of these new methods to do collaborative safety control.
(4) Multi energy flow optimal scheduling
There are several important concepts: start and stop plans, day ahead scheduling, day scheduling and real-time control. A park or city's triple supply, gas turbine and electric boiler can be started and stopped, and some equipment can be stopped to reduce the cost, which can be started and stopped according to the best start and stop plan. Then, on the basis of starting and stopping, how much output should be adjusted, which is scheduled for a day. The intra day dispatching is due to the change of wind power output and load, so the intra day dispatching is needed to adapt to the new suitable generation output and maintain the optimal output and load balance. In the end, the second level control is needed, such as network security, voltage regulation and frequency modulation. The time scale of scheduling is long, usually in 15 minutes, the control in seconds, and the time scale is short. In a multi energy flow system, there are more controllable means than a single energy system. From the point of view of source network charge storage, it can realize the comprehensive scheduling and control of cold, heat, gas, electricity, etc.
(5) Node energy price of multi energy flow
For a park or smart city, we must consider building a very good internal business model. The internal business model is not external, not up-to-date, but for users in the park. What should such a business model look like? The most scientific model is the node energy price model. The mode of node energy price first needs to determine the energy cost of each place through calculation. The energy cost includes four parts: first, the cost of energy generation; second, the cost of transmission loss; third, the cost of network congestion; fourth, the cost of multi energy coupling. Then it is necessary to calculate the energy prices of each node scientifically and accurately, including cold price, hot price, gas price and electricity price, and the prices at different times and places. Only through accurate calculation can the total energy cost of the park be significantly reduced, because the price signal can be used to guide the user's energy use. In this way, the energy cost of the whole park can be significantly reduced by flexible energy price means.
The node energy price is determined according to the marginal cost of production of the supplier. When the line is blocked, the price of each node presents different prices according to the location. The real-time price can stimulate the flexibility of the user side. Node energy price reflects the cost scientifically, which is conducive to the establishment of a fair internal market mechanism.
Reference material