This new Applications Manual, Medium voltage distribution, has been produced to help fill the gap in electrical knowledge in respect of how to safely employ medium voltage for the distribution of electrical power.
The aim is to provide an understanding of a number of key aspects at different design and construction stages of a medium voltage (11 kV) power distribution system to buildings.
It is intended to be used by practitioners in conjunction with established international wiring standards and relevant codes of practice. It will also be of interest to designers and authorities who, while not directly concerned with the design or installation of electrical systems, must understand the advice offered to them by specialists. The manual should be of value to those who wish to enhance their knowledge of electrical power and building services engineering.
Medium voltage distribution is a specialised area of power engineering. This Application Manual is one of five. The first part, AM18.1: Methods, introduced the basic principles and the common methods of medium voltage distribution. The second part, AM18.2: Equipment, explored in more detail the equipment necessary to deliver medium voltage supplies to buildings — cables, switchgear and transformers. The third part, AM18.3: Protection, considers the operation and application of medium voltage (MV) circuit protective devices such as medium voltage fuses and protection relays that control the circuit breaker configurations already introduced in AM18.2. The material also covers both current and voltage transformers that feed these protection relays. AM18.4 looked at fault calculations — necessary to determine suitable protection relay settings.
This final part, AM18.5: Protection, provides typical calculations and solutions for the protection of transformers, distribution cables, busbars, generators and motors, and includes examples so that the design of such and the calculations required to achieve protection and coordination with other items of switchgear are clear.
The authors of this guide are Les Norman (Brunel University London), Adam Rawlinson (PCS Consulting Services Ltd.), Phil Reed (RPS Group PLC).
It was peer reviewed by Derek Elliott (Insight (PFM) Limited), Brian John Hardy (independent consultant), Neil Hitchman (Vinci Construction UK Ltd.), Dr Tony Sung (Chairman, CIBSE Electrical Services Group).
Members of CIBSE receive access to the Knowledge Portal with unlimited downloads of all guides and publications.
Find out more and access your copy of CIBSE AM18.5 Medium voltage distribution: Protection via https://www.cibse.org/knowledge-research/knowledge-portal/am18-5-medium-voltage-distribution-protection-grading-2023