Protection & Control Schemes

Power transformers and switchgear are critical components in power grid substations. Control schemes relating to these components are equally important and require careful management to ensure optimum performance of the system. Protection, tapchanger control and transformer temperature control (fan and pumps) schemes could cause significant issues if not functioning correctly. Many control schemes are operational well beyond their intended design lifetimes; it is easy to find schemes which were installed more than 40 years ago. Such aged schemes become increasingly difficult to maintain as components and spare parts become obsolete. An added problem is that the network has changed since it was built to operate as a passive system with trickle-down’ power flows. These days, because of increasing levels of distributed generation, the network experiences bi-directional power flows which can cause additional problems with existing control schemes.


Fundamentals offers upgrade services for tap changer control (voltage control) and protection schemes to ensure optimum performance for the modern network. With all skills, knowledge and capabilities in-house, this service can operate as a turnkey solution to include any of the following:

  • Site Surveys
  • Network Studies – Power System Analysis
  • Relay Settings
  • Scheme Design and Drawings
  • Control Cubicle Design and Build
  • Site Installation
  • Tap Changer Motor Drive Repair and Upgrade
  • Commissioning
  • Troubleshooting


  • Quality engineering – designed to last
  • Core expertise – leaders in application of voltage control solutions
  • Fewer schemes on fixed-tap – repair of old motor drives
  • Accommodate more distributed generation – operational voltage control
  • Quicker generation connection offers – system analysis for voltage control
  • Reduce customer complaints – acceptable system voltages
  • Reduce costs related to site alarms and call-outs – optimised network voltages and operational schemes
  • Prompt resolution of issues – SME means lean and responsive
  • Turnkey service – fewer suppliers to manage