Technical principles of the hottest 110kV power gr

Technical principles of 110kV power planning

the focus of power planning is to fully consider the development positioning and needs of different regions according to the overall urban and rural planning, power planning and new energy planning, study and formulate the overall development strategy and target framework of power, based on solving the existing problems of electricity, constantly optimizing the electrical structure, improving the power supply capacity and adaptability, and fully consider the enforceability of power planning, On the premise of meeting the safe and reliable operation of electricity and ensuring the quality of power supply, it should be able to achieve a reasonable reserve of electricity supply capacity, a reasonable layout in space and a reasonable transition in time

in this paper, combined with load distribution, load characteristics and load growth, the technical principles of 110kV power planning are proposed from the aspects of power supply capacity, substation layout and electrical structure

110kv power undertakes the local digestion load, improves the 35kV and 10kV network functions, and plays a "connecting role" in regional power. It should be considered to build sufficient discharge channels for terminal loads

I. power supply capacity

1. Principle of improving imbalance and insufficiency

considering the geographical location of 110kV substation and the division of power supply area, realize partition power supply, improve the power supply capacity, transfer capacity and power receiving capacity of each partition, give priority to solving heavy-duty substation and heavy-duty line, and transfer the load of heavy-duty substation and heavy-duty line through the surrounding existing substation capacity increase, new 110kV substation and supporting liaison 10kV line. The problem of low utilization efficiency of light load transformer can be solved by changing heavy load transformer and increasing load naturally

2. Principle of capacity load ratio

meet the needs of power load growth, and enhance the power supply capacity of 110kV electricity. The capacity load ratio is controlled at 2.2 according to the guidelines, and it is controlled at 2.1 after deducting the capacity of step-up transformer. The center distance of these holes above can be broken through in the area with rapid development. In principle, the capacity load ratio does not exceed 2.5

3. Selection principle of conductor section

110kv main line section should be selected at one time according to the saturated load value in the planning area

4. Reconstruction principles of existing power channels

(1) make full use of existing power channels, protect existing channel resources and improve the transmission capacity of unit channels, and solve the problems of existing old lines in combination with new substations

(2) combined with the access of main power supply, solve the problem of limited section, improve the power supply capacity and new energy acceptance capacity, and do a good job in the construction of small section conductor transmission channel and the transformation of limited transmission capacity

distribution of the second substation

the distribution of the substation takes the overall development layout of the city as the core, and the land development, project construction and power supply development as the fixed-point sequence. The economic optimal layout is determined by the number, length and laying mode of lines at each voltage level of the substation

1. Principle of power supply radius

according to the power supply layout, load distribution, network structure, zoning and other conditions, combined with load density, space resource conditions and upper and lower power coordination, comprehensively consider the power supply radius and distribution points of 110kV substations, and each substation has a clear power supply range

urban and rural 110kV substations focus on the load, and complement the points in an orderly manner in combination with urban development. Rural 110kV substations generally bear the load of nearby villages and towns, mainly to improve the 35 kV power structure within the power supply range, and consider shortening the power supply radius of 10 kV lines in surrounding rural areas

2. Principle of voltage support

there should be sufficient voltage support in the area with concentrated electric load to improve 35kV and 10K, but the previous work has been limited to the experimental V power supply quality

3. Sequence principle

110kv stations shall be considered according to the principle of giving priority to new construction and expansion

4. The principle of mutual backup

the layout of substation considers the mutual backup and mutual support between the upper and lower levels

three electricity structure

on the premise of meeting the flexibility and reliability of power supply, try to play the role of substation and line. Considering a certain load transfer capacity is the basis for considering 110kV frame structure

1. Principle of target frame

study the 110kV target frame in combination with regional saturated load, and determine the backbone frame with clear structure, reliable power supply, flexible operation and certain flexibility, so as to promote the sustainable development of 110kV power

2. Principle of structure construction

according to the target frame, combined with the geographical location, the channel conditions affected by the wind and the enforceability, the structure construction is carried out with the 220kV substation as the center and the 110kV power supply as the support, and the mode of piecemeal power supply is adopted. Each power supply area is relatively independent under the normal mode, but it must have the ability to support each other in case of accidents to improve the applicability of the frame. According to the number, location and power supply of the substation, it will gradually transition from radial and single ring structure to T-connection and chain structure

in principle, urban and rural 110 kV substations give priority to two circuits connected to different 220kV substations. However, if the conditions are not met, the nearest two circuits can be connected to different bus sections of the same 220 kV substation

rural 110 kV substations give priority to two circuits connected to different 220kV substations. However, if the conditions are not met, the same 220 thousand test data analysis can be accessed to the nearest two times); These methods and procedures should be related to the required accuracy. The Standard Specification for inspection is to form a loop power supply mode with different sections of busbar of 1 volt generating substation, or with another 110kV substation

3. Principle of power supply access

the power supply should be connected to electricity in layers, zones and dispersion, and the substation load should be balanced nearby. In combination with power supply access, strengthen and optimize the partition electric frame, eliminate the potential safety hazards caused by electromagnetic rings at all levels, and ensure the reliable transmission of power supply and power. Configure sufficient reactive power compensation capacity to improve voltage quality. For areas rich in hydropower and wind power, technical measures should be taken to avoid voltage exceeding the limit during wet and windy periods, which will affect the safe and stable operation of power

4. Principle of lower level electricity adaptability

the new 110kV substation should be able to improve the 35kV and 10kV electrical structure in the area, and improve the 10kV power transfer capacity at the same time

the old substation maintains the existing electrical structure, but the connection between the 10kV distribution of the station and other 110kV substations should be strengthened to ensure that important loads can be transferred through medium voltage in case of high-voltage fault