Simplifying functional tests of protection relays in electrical power networks

Many of the electrical power networks have seen significant changes over the last few years. Due to the change in energy policy, today’s power is fed into these grids at many different points while the consumption can be far distant. This is making power grids increasingly complex and requires them to be operated very close to their limits. As a consequence, this results in completely new challenges for the protection system design and detailed testing of the protection system that handles these more complex protective duties is vital. Current, well established, testing solutions mainly verify the correct operation with the given relay settings. These so called functional tests generally cover steps such as commissioning or parameterisation of the respective relays. The rising demands include a multifaceted procedure that starts with investigating the fault and operation scenarios followed by choosing the appropriate protection concept. One of the greatest challenges of this process is calculating the settings of each component and eliminating disturbing interactions before commissioning the system. This inherent complexity raises the likelihood of errors during protection system development. These errors that crept in during the complete design process cannot be found with the functional testing methods.