A Non-Intrusive Approach for Enhancing Power-System Frequency Stability

This paper presents a novel protection strategy for assuring power-system frequency stability. After many years of use, the existing (static) under-frequency load-shedding concept has proven to be reliable and fast. However, it does not adapt well to volatile operating conditions, which might often lead to a system collapse. This developed into a major obstacle, since operational conditions of modern power systems are persistently subjected to fast and unpredictable changes. Therefore, there is a need to introduce a new capability in under-frequency load-shedding that would be able to fine-tune the mismatch in active power in any conditions. From the practical aspect, a systematic implementation of improvements should not threaten system stability. In terms of cost, a minimum intervention in the existing concept is desirable. This is why we developed an effective upgrade of the existing concept by introducing a specialized group of intelligent electronic devices supported by a principal component analysis technique. This group should be operated alongside the existing solution to monitor the actual frequency conditions and to take over power-balancing when fine-tuning is required. This supports the existing load-shedding and improves the process of frequency stabilization.