Competency in Substation Design (Control, Protection and Facility Planning)

Overview

Substations are critical assets in any power system and serve as important nodes in a transmission and distribution network. Substations, therefore, handle multiple voltages in a given location and link two or more systems of different voltages.

This Competency in Substation Design (Control, Protection and Facility Planning)  course from the Engineering Institute of Technology  will focus on subsystems that perform essential functions in substations. These include earthing and grounding, lightning protection of outdoor equipment and substation buildings, power system protection, control, and interlocking equipment, including the auxiliary power sources and various switchyard facilities. These include foundation, structures, cable routing, lighting, fire protection and surveillance equipment. 

Earthing of a high voltage switchyard requires careful design as it has a direct bearing on safety. The design approach to switchyards will be discussed, and the basic methods of calculation will be outlined. Lightning is a common threat to substation equipment and supply reliability, as overvoltage surges can result in insulation failure or spark over. While lightning cannot be prevented, its effects can be minimized by proper lightning and surge protection measures.

Any electrical equipment is susceptible to insulation failures. Protection against such failures and the resulting short circuits is a vital need in power systems. The various protection options available to the designer and the protection of busbars, transformers, and substation feeders will be discussed.

Another essential system is the control of switchyard equipment and the required auxiliary power supply. AC auxiliary power is used for the operation of isolators and disconnectors, the operating mechanism of circuit breakers, and substation lighting. The essential functions are powered through DC supply backed with batteries for reliability. This includes control, annunciation and protection functions, breaker close and trip commands, and in some cases, emergency lighting.

A switchyard has to be adequately planned by preparing the site, measuring earth resistivity required for earthing design and optimization, earthwork, foundations, cable trenches inside the switchyard, draining arrangements, etc. These aspects will be covered in detail during the course. We will also discuss gas-insulated switchgear as an alternative to outdoor open type switchyards.

This course will also cover selecting and applying appropriate power system protection to protect equipment and personnel from abnormal system conditions, including short circuits and earth faults.

Certification

To obtain a certificate of completion for EIT’s Professional Certificate of Competency course, students must achieve a 65% attendance rate at the live, online fortnightly webinars.  Detailed summaries or notes can be submitted in lieu of attendance.  In addition, students must obtain a mark of 60% in the set assignments which could take the form of written assignments and practical assignments. Students must also obtain a mark of 100% in quizzes.  If a student does not achieve the required score, they will be given an opportunity to resubmit the assignment to obtain the required score.