NB/T 10345-2019Code for design of high voltage electrical equipment selection and arrangement for hydropower plants (English PDF)

Foreword

This document was issued on 30 December 2019 by the National Energy Administration of the PRC and takes effect on 1 July 2020.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 27.140, Chinese classification P 59.

It replaces DL/T 5396-2007, which is superseded.

This code was revised by the drafting group in accordance with the requirements of the Notice of the National Energy Administration on Issuing the 2016 Plan for the Formulation and Revision of Industry Standards in the Energy Field (Guo Neng Ke Ji [2016] No. 238). The revision was carried out after extensive investigation and research, a careful summary of practical experience, and wide solicitation of opinions.

The main technical contents of this code are: basic requirements, selection of high voltage electrical equipment, and arrangement of high voltage electrical equipment.

The main technical contents revised in this edition are listed in the four items that follow.

The terms disassembly-transported power transformer and take-over current were added to the terminology clause.

Provisions were added covering solid-insulated tubular busbars, disassembly-transported power transformers, station service (auxiliary) transformers, electronic voltage transformers, electronic current transformers, insulators, bushings, line traps, gas-filled metal-enclosed switchgear and high voltage fuses.

The scope of application of the code was revised from a nominal voltage range of 3 kV to 500 kV to a nominal voltage range of 3 kV to 750 kV.

The altitude correction formula for the external insulation of electrical equipment, the classification of pollution severity levels and the requirements for the specific creepage distance were revised.

This code is under the administration of the National Energy Administration. It is proposed by, and under the routine management of, the China Renewable Energy Engineering Institute (Hydropower and Water Resources Planning and Design General Institute).

The Standardization Technical Committee for Hydropower Electrical Design of the energy industry is responsible for the interpretation of the specific technical contents. Comments and suggestions arising during implementation should be sent to the China Renewable Energy Engineering Institute, No. 2 Liupukang Beixiaojie, Xicheng District, Beijing, postcode 100120.

Chief development organization of this code: PowerChina Chengdu Engineering Corporation Limited (China Power Construction Group Chengdu Engineering Investigation and Design Research Institute Co., Ltd.).

Participating development organization of this code: PowerChina Northwest Engineering Corporation Limited (China Power Construction Group Northwest Engineering Investigation and Design Research Institute Co., Ltd.).

Chief drafting staff of this code: Wen Fengxiang, Yang Hong, Huang Kai, Qin Ying, Zhao Huimei, Fang Lei, Li Yong, Wang Yaohui, Hou Yanshuo, Sang Zhiqiang, Zhang Li, Zhang Yong, Ju Lin and Song Linli.

Chief reviewing staff of this code: Yu Qinggui, Fang Hui, Feng Zhenqiu, Kang Benxian, Wang Jinfu, Chen Yinqi, Shi Fengxiang, Xia Fujun, Yang Jianjun, Sun Fan, Wang Xiaobing, Wang Yong, Shao Guangming, Wang Huajun, Xie Xiaohui, Du Gang and Li Shisheng.

Publication Data and Approval Record

Standard designation printed on the cover: NB/T 10345-2019, an energy industry standard of the People's Republic of China.

Chinese title on the cover: shui li fa dian chang gao ya dian qi she bei xuan ze ji bu zhi she ji gui fan.

Official English title on the cover: Code for Design of High Voltage Electrical Equipment Selection and Arrangement for Hydropower Plants.

Classification data on the cover: ICS 27.140; Chinese standard classification code P 59; the document belongs to division P.

Issued on 30 December 2019 and implemented from 1 July 2020. Issuing authority: National Energy Administration.

This code replaces DL/T 5396-2007, which is superseded from the date of implementation of this code.

Chief editing department: China Renewable Energy Engineering Institute (Hydropower and Water Resources Planning and Design General Institute). Approving department: National Energy Administration. Date of entry into force: 1 July 2020.

Published by China Water and Power Press, Beijing, 2020.

Approval record: Announcement of the National Energy Administration No. 8 of 2019, dated 30 December 2019, which approved 152 energy industry standards listed in Attachment 1 and the English versions of 39 energy industry standards listed in Attachment 2.

In the catalogue of industry standards forming Attachment 1 of that announcement, this code is item 22: standard number NB/T 10345-2019, standard replaced DL/T 5396-2007, date of approval 30 December 2019, date of implementation 1 July 2020.

Structure of the Document

The code is organized in five numbered chapters followed by three closing parts, and the official English table of contents printed in the document runs to 61 numbered pages of main text and explanatory material.

Chapter 1, General Provisions, occupies page 1 and sets out the purpose, the field of application from 3 kV to 750 kV, and the relationship with other current national standards.

Chapter 2, Terms, occupies page 2 and defines five terms used throughout the code.

Chapter 3, Basic Requirements, runs from page 3 to page 8 and is divided into General Requirements on page 3, Electrical Requirements on page 3, Mechanical Requirements on page 5 and Climatic and Environmental Conditions on page 6.

Chapter 4, Selection of High Voltage Electrical Equipment, runs from page 9 to page 37 and is the longest chapter of the code, divided into twenty subclauses.

The equipment-selection subclauses of Chapter 4 cover, in order, Conductor, Main Transformer, Auxiliary Transformer, Generator Circuit Breaker, Electrical Brake Switch, High Voltage Circuit Breaker, High Voltage Load Switch, and High Voltage Disconnector and Earthing Switch.

They continue with Gas-Insulated Metal-Enclosed Switchgear, AC Metal-Enclosed Switchgear, High Voltage Fuse, Voltage Transformer, Current Transformer, Shunt Reactor, Current-Limiting Reactor, Generator Neutral Equipment and Surge Arrester.

The chapter closes with Bushing and Insulator on page 36 and Line Trap on page 37.

Chapter 5, Arrangement of High Voltage Electrical Equipment, runs from page 38 to page 55 and is divided into Arrangement of Main Electrical Equipment on page 38, Clearance Requirements on page 43, Passway and Fence on page 51, and Requirements for Buildings and Structures on page 54.

The closing parts are Explanation of Wording in This Code on page 56, List of Quoted Standards on page 57, and the Addition, Explanation of Provisions, beginning on page 61.

The standards quoted in the opening chapters of the code include NB/T 35043 for the calculation of three-phase AC short-circuit currents in hydropower projects, GB/T 311.1 for insulation co-ordination, DL/T 593 for the common technical requirements of high voltage switchgear and controlgear, and GB/T 11604 for the measurement of radio interference of high voltage electrical equipment.

1 Scope

NB/T 10345-2019 governs the selection and physical arrangement of high voltage electrical equipment in hydropower plants, replacing DL/T 5396-2007. It is the code an electrical designer applies once the single line diagram is settled and the question becomes which apparatus to buy and where to put it - a question that in a powerhouse is constrained by the cavern or building around it, by the humidity and the risk of flooding, and by the access needed to maintain machines that may be a hundred metres underground. The code sets the general provisions and the basic requirements, then the conditions against which equipment is selected: rated voltage and current, short circuit withstand both thermal and dynamic, insulation coordination, altitude and ambient correction, pollution level and seismic requirement. It then works through the equipment - generator circuit breakers, high voltage circuit breakers and disconnectors, instrument transformers, surge arresters, bushings and insulators, generator neutral equipment, busbars in their rigid, flexible and enclosed forms, gas insulated switchgear, power and station service transformers, and the cables and their terminations. For each it gives the selection criteria and the calculation to be performed. Arrangement follows: clearances in air, the layout of indoor and outdoor switchgear, the GIS hall, the transformer bays and their fire separation, the cable routes, earthing and the access and safety distances for operation and maintenance.

1.0.1 This code is formulated in order to standardize the design of the selection and arrangement of high voltage electrical equipment in hydropower plants, so that such design is safe and reliable, technically advanced and economically rational.

1.0.2 This code applies to the design of the selection and arrangement of high voltage electrical equipment with a nominal voltage of 3 kV to 750 kV in newly built, rebuilt and extended hydropower plants.

1.0.3 In addition to complying with this code, the design of the selection and arrangement of high voltage electrical equipment in hydropower plants shall also comply with the provisions of the relevant current national standards.

2 Terms

2.0.1 Incoming line. The line led from the main transformer to the high voltage switchgear.

2.0.2 Outgoing line. The line led from the high voltage switchgear to the equipment of the high voltage outdoor switchyard.

2.0.3 Connecting line. The line led from switchgear of different voltage levels within a hydropower plant to the interconnecting transformer, or the line between items of switchgear of the same voltage level installed at different arrangement locations.

2.0.4 Disassembly-transported transformer. A power transformer which, because of limitations imposed by transport conditions, has to be disassembled for transport after all the factory tests have been completed at the works, and which is assembled again on the installation site.

2.0.5 Take-over current. The current at the point of intersection between the time-current characteristic curves of two overcurrent protective devices.