Polaris Power Transmission and Distribution Network News: Abstract: This article reviews the development history of typical design of the 10kV distribution network project of State Grid Corporation of China, compares the differences of typical design results of distribution projects, overhead line projects and cable laying projects at different stages, introduces the basic principles of typical design preparation, and focuses on analyzing the characteristics of typical design results of 2015 version in terms of design depth, uniformity, applicability and progressiveness, Outlook on the development direction of typical design for 10kV distribution network engineering.
Introduction
The distribution network is an important component of the power grid, which is an important infrastructure for ensuring the distribution, deployment, and utilization of electricity. With the continuous development of China's economy and society and the increasing living standards of the people, the development of the power grid faces greater opportunities and challenges, and the requirements for power grid planning and construction are increasing. In 1998, China launched the urban and rural distribution network renovation project, which improved the situation of "heavy power generation, light supply, and ineffective use" in the planning and construction of the power grid. In 2015, China launched the Action Plan for the Construction and Renovation of Distribution Networks (2015-2020), which proposed ten key tasks such as "strengthening unified planning, improving standard systems", and the development goal of building distribution network facilities that are "urban-rural coordination, safe and reliable, economically efficient, technologically advanced, and environmentally friendly", pointing out the direction for future distribution network planning and construction. The number of 10kV distribution network projects is large, the individual projects are small, and the construction period is short. With the continuous increase in investment in distribution network construction, the efficiency and quality of engineering construction will become the key to effectively implementing China's distribution network construction and renovation action plan. State Grid Corporation of China has always adhered to the concept of "three connections and one standard" (universal design, universal equipment, universal cost, and standard process) in power grid construction projects, taking the typical design results of 10kV distribution network projects as the leader, continuously improving and improving the efficiency and quality of distribution network engineering construction. This provides a strong guarantee for continuously improving the design quality of distribution network engineering during the 13th Five Year Plan period, and thereby improving the quality of engineering construction.
This article first reviews the typical design development process of State Grid Corporation of China's 10kV distribution network project, compares and analyzes the differences in typical design results of distribution engineering, overhead line engineering, and cable laying engineering at different stages, analyzes the characteristics of typical design results in the 2015 version, and looks forward to the development direction of typical design for 10kV distribution network engineering.
1. Typical Design History of 10kV Distribution Network
1.1 The typical design of State Grid Corporation of China's 10kV distribution network project at the headquarters level began in 2002 and has gone through three main stages of development.
1) In the first stage (2002-2006), the main focus was on summarizing and promoting experiences. The predecessor of State Grid Corporation of China, the Power Generation and Transmission Operation Department of State Grid Corporation of China, organized the completion of the Typical Scheme Atlas for 10kV Switching Stations, Distribution Stations, Box type Substations, and Cable Branch Boxes by systematically summarizing the design achievements of urban and rural power grid projects.
2) The second stage (2006-2012) focused on building a typical design technology system. In 2006, the Infrastructure Department of State Grid Corporation of China organized the "Typical Design of State Grid Corporation of China's Transmission and Transformation Engineering", which included a 10kV distribution network engineering section, a 10kV and 380/220V overhead distribution line section, and a cable laying section. In 2012, the Agricultural Power Work Department of State Grid Corporation of China organized the completion of the "General Design and Construction Drawing Book for 10kV Column mounted Transformer Stations in State Grid Corporation of China's Agricultural Power Grid", which standardized the design results of the construction drawings for column mounted transformer stations.
3) In the third stage (from 2013 to present), the top-level design and improvement were highlighted. In 2013, the Operation and Maintenance Department of State Grid Corporation of China completed the Typical Design of Distribution Network Engineering (2013 Edition) 10kV Distribution Engineering Division, Overhead Line Division, and Cable Division, as well as the Typical Design of 380/220V Distribution Network Engineering. In 2015, based on the application effect and improvement needs, the Typical Design of Distribution Network Engineering (2013 Edition) was deepened and improved.
1.2 At the provincial level, in 2007, State Grid Beijing Electric Power Company completed the design of the distribution switch station, distribution room, overhead lines, and cables as part of the planning and design section of the distribution network technical standards (including planning, design, equipment selection, construction acceptance, and operation and maintenance). In 2010, State Grid Shandong Electric Power Company completed the typical design of the direct supply medium and low voltage distribution network project, including two volumes of substation engineering and line engineering (including two parts of overhead and cable); State Grid Gansu Electric Power Company has completed the typical design of Gansu Electric Power Company's rural power grid project, including two parts: 10kV substation and overhead lines. In 2012, State Grid Hunan Electric Power Company completed the standardized design results of the 10kV and below distribution network project of Hunan Electric Power Company, including 5 parts: 10kV distribution, overhead lines, cables, 0.4kV and 10kV distribution automation in the distribution station area; State Grid Shanghai Electric Power Company has completed the general design drawings for the new residential area power supply supporting project and the general design drawings for the expansion project of non residential power users. In 2013, State Grid Jiangsu Electric Power Company completed the standardized design of construction drawings for 10kV and 20kV distribution projects, the standardized design of power supply and distribution facilities for new residential areas, and the standardized design of expansion and connection projects for medium and low voltage power users; State Grid Zhejiang Electric Power Company has completed four sub volumes: 10kV and 20kV distribution projects, 10kV overhead distribution lines (including four design scenarios of hills, mountainous areas, coastal and plain areas, and lakes and swamps), cable lines, and 380/220V distribution lines. In 2014, State Grid Shanghai Electric Power Company completed the general design drawings for distribution network engineering, including transformer and distribution, overhead lines, distribution facilities in residential buildings, cable lines, fiber optic to home and residential area piping.
2. Deepening of Typical Design Achievements for 10kV Distribution Network
2.1 Preparation principles of typical design The basic principles of typical design of the 10kV distribution network project of State Grid Corporation of China are: unified standards, wide coverage, safety and reliability, energy conservation and environmental protection, environmental coordination, advanced application, cost reduction, and coordination and unification of unity and applicability, reliability, progressiveness, economy, and flexibility. Unification: The basic scheme of typical design is unified, and the construction standards are unified. Applicability: Typical designs should comprehensively consider the actual situation in different regions, have broad applicability in the company's system, and be applicable to different scales, forms, and external conditions within a certain period of time. Reliability: The technical solution obtained through module splicing is safe and reliable. Progressiveness: promote and apply mature and applicable new technologies, new equipment and new materials; Considering the development needs of distribution automation and adapting to the requirements of distributed power sources and electric vehicle charging and swapping facilities. Economy: Taking into account the initial investment and long-term operating costs of the project, we strive for the optimal economic benefits for the enterprise during the project's lifespan. Flexibility: Reasonable module division, flexible and standardized interfaces, diverse combination schemes, convenient addition and reduction, and flexible applicability.
2.2 The Unification and Standardization of Typical Designs The typical design technical schemes for 10kV distribution network engineering are becoming increasingly refined and reasonable. Taking 10kV switchgear facilities as an example, the typical design results of the 2002 version are divided into 14 design schemes based on electrical main wiring, switchgear equipment types, and incoming and outgoing lines; The 2006 version is divided into two categories: indoor (KB) and outdoor (KA), and is subdivided into 16 design schemes based on main wiring, incoming and outgoing lines, equipment types, and civil engineering layout; The pre installed features of outdoor switch facilities in the 2013 version are divided into two categories: switch stations (KB) and ring network units (HA), with a total of 17 design schemes refined; The 2016 version considers the functional characteristics and role of switch facilities in the power grid, and is divided into three categories: switch stations (KB), ring network rooms (HB), and ring network boxes (HA). There are a total of 8 design schemes based on main wiring, incoming and outgoing lines, equipment types, and civil layout. In the design scheme, the interchangeability and standardization of electrical equipment are constantly being strengthened. Taking the 2016 version of the ring network room as an example, the design size of the gas insulated load switchgear in all technical solutions is uniformly 500mm × 850mm × 2000mm, the uniformity of design results and equipment interchangeability have been further strengthened; The floor height of the ring network room for independent buildings is uniformly 3.6 meters. By comparing the typical design results of 2006, 2013, and 2016, it can be seen that the design depth of the typical results of 10kV distribution network engineering is gradually deepening. The 2015 version of typical design results shows that the electrical part of the distribution project has reached the depth of the construction drawings, and the electrical secondary content has been added to reach the preliminary design depth. Taking the switch station as an example, a typical technical solution includes 23 drawings for electrical primary, civil, and electrical secondary; Add cement pole cross arms and all iron accessories processing drawings for the overhead line section, as well as structural drawings for steel pipe poles and narrow foundation towers, for reference by designers; The cable laying section includes all modules except for the pull tube module that have reached the depth of the construction drawing. It also provides a method for matching and calculating the cable well module and cable duct module, which is used to guide designers in selecting the cable well module correctly.
2.3 The applicability of typical design results has been continuously improved from the 2006, 2013, to 2016 versions after nearly 10 years of development. The typical design results of 10kV overhead lines always adhere to the design concept of "one pole with multiple heads and one pole with multiple uses". While optimizing and simplifying pole types, the types of pole types are constantly enriched. The 2016 version of the typical design results has expanded the maximum applicable span of 10kV stay wire straight cement double poles and stay wire corner cement double poles to meet the design requirements of single circuit lines with larger spans in hilly and mountainous areas, as shown in Figure 3; Expand the design of 10kV single circuit and double circuit narrow base towers with a maximum applicable span of 120m to meet the design needs of mountainous and hilly areas where urban green belts and tower transportation are inconvenient. The cable section enriches the design drawings of the top pipe module and the design drawings of the miniaturized octagonal four-way well module, and provides the selection principles for cable channel types considering urban level and power supply areas (see Table 1) for use by designers, improving the practicality and applicability of the design results.
2.4 progressiveness of typical design achievements Typical design compilation closely tracks the development of distributed generation and the application of distribution automation technology in distribution network. The 2016 version of the distribution engineering results inherits the 2013 version of the station terminal unit (DTU) equipment layout results, adds DTU aviation plug-in interface, and improves the standardization level of intelligent distribution network; In the 2013 version of the distribution room facilities, anti islanding devices for distributed power sources were considered to ensure reliable access to distributed power sources and safe operation of the distribution network. In the 2015 version of the typical design results for overhead lines, considering the characteristics of A+, A-E power supply areas, the application scenarios and configurations of feeder terminals (FTUs) were added, and the selection of primary and secondary equipment for terminal matching was clarified to improve the standardization level of power distribution automation construction. Design drawings were drawn, and the cable laying section considered the communication needs of power distribution automation and other systems. For example, the cable laying module was designed with a communication dedicated pipe hole with a diameter of 100mm, Simultaneously combined with plum blossom tube materials, used for laying optical cables. 3. The development direction of typical design for distribution networks will be accompanied by the continuous improvement and perfection of "three new" (new technology, new materials, new processes) development. In 2015, State Grid Corporation of China compiled a catalog of demonstration materials for 10kV equipment and materials, aimed at encouraging the demonstration and application of "three new" achievements in distribution network engineering. The catalog of demonstration application materials includes a total of 52 types of materials, including rare earth high-speed iron aluminum alloy cables, distribution automation control devices, column mounted reactive power complete sets, 10kV static reactive power generators (SVGs), high overload distribution transformers, ultra-high performance concrete poles, SF6 free ring network cabinets, solid insulation ring network cabinets, modified thermoplastic plastics, and fiberglass composite cable protection pipes. With the application of "three innovations" in distribution network engineering, typical design modules will continue to innovate through continuous summarization and finalization. The modularization, integration, and complete procurement of materials for the high and low voltage parts of distribution network engineering will be the future development direction. In the 2016 version of the Distribution Engineering Standard, the design scheme for the column mounted transformer station has achieved modularization and complete set. The design scheme can be combined based on the modules of the transformer, fuse, lightning arrester, and high-voltage lead. The bidding for the complete set of materials for the column mounted transformer station has been achieved by compiling module and complete set material codes. The complete procurement of outdoor ring network boxes and prefabricated box type substations in power distribution engineering has been achieved. Through deep integration with distribution automation station terminals (DTUs) and transformer terminals (TTUs), integrated design and procurement can be achieved. Future overhead line projects can also consider modular design and complete procurement based on pole types, cross arms (including insulators and lightning protection), conductors (wires and connecting fittings), stay wires (stay wires and connecting fittings), equipment (switchgear, racks and iron accessories), and pole mounted distribution terminals (FA, connecting fittings box, communication module). The universality and interchangeability of distribution equipment will continue to be strengthened, and future typical design achievements will strive to achieve universal interchangeability of similar equipment from different equipment suppliers. The 2016 version of the standard design results attempted to standardize the size of metal movable switchgear, and provided recommended parameters such as electrical installation interfaces, busbar arrangement, height, and spacing for feeder cabinets, busbar equipment cabinets, station transformer cabinets, and segmented equipment cabinets, in order to achieve universal interchangeability of the same equipment from different equipment suppliers. The future typical design compilation will further standardize the electrical installation parameters of outdoor ring network boxes, prefabricated box type substations, ring network cabinets, column load switches, column circuit breakers, and other equipment. At the same time, standardized civil engineering, brackets, etc. will be designed to improve the universal interchangeability of equipment and its ancillary iron components. The application of 3D digital design technology will promote the continuous progress of classic design achievements. When determining the design scheme of the column mounted transformer platform in the 2016 version of the typical design, three-dimensional digital design technology was used, and the design results were clear at a glance. It can intuitively simulate the electrical distance of high and low voltage pile head wiring, drop type fuses, lightning arresters, grounding rings and other equipment of the transformer, greatly improving the accuracy of the design scheme results.
4. The typical design of 10kV distribution network engineering is the main component of the "three connections and one standard" of the distribution network. The typical development of future distribution network engineering will revolve around the needs of unity and differentiation, accompanied by the advancement of new technologies, materials, and processes, equipment interchangeability, modular materials, and integrated procurement, and other technical requirements. With the help of advanced tools and methods such as digital technology, new technologies will be continuously introduced. The improvement and continuous improvement of typical design results have a positive promoting effect on meeting economic and social development, improving the quality and efficiency of distribution network engineering construction, and supporting the construction and renovation of the national distribution network.