Grid Planning Trends! Main Problems Faced by Work in the New Era

Grid planning, also known as transmission system planning, is based on load forecasting and power supply planning. Power grid planning determines when and where to invest in what type of transmission lines and the number of circuits to achieve the required transmission capacity within the planning cycle, and to minimize the cost of the transmission system on the premise of meeting various technical indicators.

1. Introduction to grid planning

Grid planning, also known as transmission system planning, is based on load forecasting and power supply planning. Power grid planning determines when and where to invest in what type of transmission lines and the number of circuits to achieve the required transmission capacity within the planning cycle, and to minimize the cost of the transmission system on the premise of meeting various technical indicators.

2. Classification of grid planning

Power grid planning is classified according to time and can be divided into short-term planning, medium-term planning and long-term planning.

In addition, it can be classified according to different professions, such as various special plans such as communication planning, marketing planning, and coal mine power supply planning.

The short-term plan is divided into 1-5 years, and the content of the plan is more specific and careful, which can be directly used to guide the construction. The general power grid 5-year plan is synchronized with the 5-year plan of the national economy. For example, the Eleventh Five-Year Plan, the Twelfth Five-Year Plan, etc.

Medium-term planning is generally 5-10 years.

Long-term planning needs to consider the development situation that is longer than the construction cycle of power transmission and transformation projects, and the general planning is 6-30 years. Long-term power grid planning needs to enumerate various possible excessive aversions, estimate the impact of various uncertain factors, and so on. The long-term planning scheme does not necessarily have to be implemented intact during construction. Due to changes in objective conditions or the environment, the planning scheme will also continue to change.

3. The method of grid planning

The final result of power system planning mainly depends on the original data and planning methods. Without sufficient and reliable original data, it is impossible for any excellent planning method to obtain a realistic planning scheme. An excellent power system planning must be based on solid preliminary work, including the collection and arrangement of system power load data, local socio-economic development, raw data on power points and transmission lines, and so on.

In terms of planning methods, our country is in the state of using both traditional planning methods and optimal planning methods.

4. In the new era of power grid planning, the power grid planning work faces the following main problems

4.1 For the coordination of power grid planning, it is necessary to study how to grasp and coordinate power grid planning and power grid planning as a whole, so as to ensure the coordinated and simultaneous development of power grid construction and power grid construction;

4.2 Differentiated power grid planning issues, it is necessary to focus on improving the power grid's disaster resistance against catastrophic disasters in power grid planning;

4.3 The evaluation index system of power grid planning scheme is not perfect. Power grid planning must pay attention to the reliability and security of the power grid, while in the electricity market environment more attention should be paid to the economy of the scheme. The development of smart grid requires the evaluation of the environmental protection characteristics of the planning scheme, etc.;

4.4 There is a serious shortage of informatization and intelligent support for power grid planning. Power grid planning lacks a unified data platform support, and data collection takes a long time. Visualization techniques such as geographic information systems (GIS) have limited use. There is no automatic data interaction between power grid planning and power grid simulation. Except for urban distribution network planning, there is a lack of technical support for intelligent auxiliary decision-making of power grid planning.

5. Feasibility of grid planning

In terms of finance, three issues should be considered: the recovery rate of construction investment, the economic operation of the power grid, and sustainable development.

Construction investment should pay attention to return, pay attention to recovery rate. Whether the construction investment of the power grid is reasonable and whether it satisfies the economic operation of the power grid. The recovery rate of construction investment and the economic operation of the power grid are for specific engineering projects, and the sustainable development problem is to determine the requirements for urban network planning within a certain period or within a certain financial cycle from the perspective of the overall action and development of power supply companies. During this period, the overall scale and level of urban network planning work.

Generally speaking, in urban network planning, the medium- and long-term scale is firstly resolved based on the perspective of sustainable development, and then the specific planning projects are determined according to the economic operation of the power grid. Equipment selection. Among them, the specific parameters of theoretical calculations such as the discount rate are determined according to the development of the national economy and the interest rate level of the People's Bank of China. On this basis, research and determine the optimal network connection mode, investment level and investment time schedule of the power grid, so that the power supply capacity of the power grid, the quality of power supply and the reliability of power supply can meet the electricity demand of users, and the electricity price is lower than the social marginal price. Provide high-quality electric energy to customers at a low cost.

In addition to meeting the above-mentioned goals, urban network planning must also be coordinated with urban planning to meet the needs of the overall development of the city.

The urban network planning objects should be classified and analyzed in terms of region, industry, and time. According to the state of economic development, it is advisable to divide urban network planning objects into three categories: old urban areas, new urban areas, and quasi-urban areas.

The old urban area is a municipal planning forming area, and the load is easy to grasp. The municipal government's municipal planning work is only a partial adjustment. Power supply companies can make full use of the existing power grids and equipment at all levels to do a good job in power supply.

The new urban area is the expansion area of the old urban area. It is a township that is adjacent to the old urban area in the process of promoting economic development. The municipal government's municipal planning work for it is an overall adjustment. Municipal planning can refer to municipal planning and on the basis of load forecasting, according to the load characteristics of the city or similar areas at home and abroad to do a good job in planning and power grid construction.

Zhuncheng District is an economically developed township, which can bring huge load, electricity consumption and benefits to power supply companies. Although it may not be included in the municipal planning by the municipal government, this is also something that power supply companies must consider. It can be based on load forecasting. On the basis of the load characteristics of this city or similar areas at home and abroad, the planning work and power grid construction work should be done well.

Different industries often have different power consumption characteristics, so industry classification is also very important in urban network planning. It is generally divided according to its use: residential, commercial, and various industries.

The power consumption of the same user at different times is different, which should be fully taken into account in the planning.

Load forecasting is the basis of urban network planning, and plays a key role in determining the long-, medium-, and short-term scale of planning, specific projects, and the quality of planning.

There are many methods of load forecasting, and each method has its own characteristics, scope of application and limitations. In order to improve the accuracy of load forecasting, load forecasting models of various forecasting methods can be established, each forecasting method is compiled into software, and a forecasting method library is established. In actual forecasting, various economic forecasting data, planning and historical data collected will be forecasted by means of calling the forecasting main database, using various methods, and then aiming at the smallest forecasting error, according to the macroeconomic situation and experience. The weights of various methods, the weighted average of various forecast results, is the so-called "combined forecast", so that more accurate load forecast results can be obtained.

In order to ensure the efficiency and operability of power grid investment, urban network planning should start with municipal planning on the basis of existing loads, and serve municipal planning during the planning process. Specifically, in the course of operation, the load forecasting should be combined with partitioning, business division and time-sharing forecasting. The specific location of different industries in the city and the load of specific years should be studied, so that the planning and construction of power supply equipment such as substations and lines can meet the needs of load growth. The specific method is to decompose the total load in time and space. According to the urban planning, a spatio-temporal geographic model can be established. With the help of GIS application, the total load can be decomposed into partition loads and implemented in specific locations of the city. The spatio-temporal geographic model of load considers the industry type and number of electricity customers as a function of location, while the electricity consumption of each customer is a function of time. In this way, the change of load can be grasped in terms of time, space, and ontology, and the work of load forecasting can be done more accurately.

Due to the possibility of providing good services to power supply users, all regions have increased investment in distribution networks, so power distribution planning has become the main content of planning, and the layout of substations should also fully consider power distribution planning, because reasonable distribution of substations can reduce The investment in the distribution network of power supply enterprises can reduce the investment in power grid construction as a whole.

6. Trends in grid planning

The theoretical calculation of power grid planning has successfully used genetic algorithm, simulated annealing and other multi-parameter parallel algorithms for line planning, and applied it in practice, achieving good results and ensuring the optimal choice of planning schemes. This will be the trend of urban network planning.

While urban network planning is serving and obeying municipal planning, power supply enterprises should also come up with their own planning standards according to their own financial conditions, and communicate with municipal planning departments in a timely manner, so as to avoid excessive emphasis on the improvement of science and technology by municipal planning departments. Municipal planning puts forward too high technical standards for power supply companies, which makes power supply companies bear higher investment.

For a power supply company with huge fixed assets, in order to ensure a good asset-liability ratio and profit margin, it must strive for the realization of diversified investment in urban power grids. This not only affects the operating performance of the power supply enterprises in that year, but also affects the sustainable development of the power supply enterprises.

Although the government has carried out urban network transformation work on urban power grids, it has solved many problems existing in power grids at all levels, improved the health level of lines, ensured the reliability of power supply, and ensured the safe use of electricity by the masses. welcome. But with the development of the economy and the improvement of people's living standards, it is only a matter of time before the power supply increases further. Power supply companies are facing enormous pressure in urban network planning and construction during this period of power reform. Therefore, during the transition period of power reform, we should fully consider the use of existing policies and strive for policies to diversify investment in urban power grids.

This issue should be taken into consideration especially in the investment and construction of quasi urban areas and new urban areas. The new power supply projects in these areas often have a wider power supply area than the old urban areas, but the load density is low, and their investment returns will not be very good. Therefore, power supply companies should do the same as other public utilities in the construction of projects in such areas , not only to strive for investment from governments at all levels, but also to strive for various preferential policies, such as low-interest loans, tax reductions and exemptions, increased electricity sales prices, lowered on-grid electricity prices, and increased investment in power grids by new users.

The potential of economic development indicates the pressure of substantial expansion of the urban power grid, which is completely different from the established urban-high power grids in western developed countries. Therefore, power supply companies should face the reality and make use of what the country has imposed on other public utilities in the process of economic development. The supporting policies adopted are essential for the planning and construction of urban power grids in terms of urban power grid planning, especially in the planning of new urban areas and quasi-urban areas, and to strive for more diversified investment.

Striving for diversification of urban network investment is a favorable guarantee for doing a good job in urban network planning. The diversification of urban network investment is also a problem that power supply companies must coordinate and solve after entering the market economy.

Under the condition of market economy, when planning and designing the urban network, the power supply enterprises should do a good job of economic analysis from all stages and levels of the planning under the premise of fulfilling social responsibility and benefits, so that the viewpoint of economic benefits can be included in the planning of the urban network. Only in this way can the benefits of power supply enterprises grow organically, the sustainable development of power supply enterprises can be guaranteed, and the role and significance of planning can be fully revealed. Not only that, but power supply enterprises should take advantage of the inherent laws of the market economy, base themselves on reality, change from passive to active, make full use of various factors, influence policy-making departments, and strive for more policies to be used in the planning and reconstruction of urban power grids.