Design and validation of a wide area monitoring and control system for fast frequency response

This paper presents the design and validation of a Wide Area Monitoring and Control (WAMC) system for Fast Frequency Response (FFR) to address the challenges associated with reduced and non-uniformly distributed inertia in power systems. The WAMC system, designed for the power system in Great Britain, is termed "Enhanced Frequency Control Capability (EFCC)". It uses real time measurements from Phasor Measurement Units (PMUs) to monitor the system state in order to rapidly detect frequency disturbances and evaluate the magnitude of power imbalances. The impact of the disturbances on different parts of the network is considered to subsequently allocate the required response for different regions of the network, all within less than one second from the initiating event. The capabilities and characteristics of different resources (e.g. wind, energy storage, demand, etc.) are also evaluated and taken into account to achieve a suitable, optimized and coordinated response. Case studies using highly realistic hardware-in-the-loop setups are presented and these demonstrate that the proposed system is capable of detecting frequency events and deploying appropriate and coordinated responses in a timely fashion even with degraded communication conditions, thereby effectively enhancing the frequency control in future low-inertia systems and permitting higher penetrations of low-carbon and low-inertia energy sources

Online Detection of Out-of-Step Condition Using PMU-Determined System Impedances

This paper presents a robust and adaptive out-of-step (OOS) protection algorithm, using wide-area information, that can be applied on tie-lines in observable power systems. The developed algorithm is based upon real-time computation of the system impedance and makes use of the well-known power-angle characteristic. In this way, a setting-less OOS concept in real-time environment is developed, which is applicable for tie-lines in an arbitrary power system. Furthermore, the developed protection algorithm is installed on hardware and is verified by numerous tests. The performance of the new hardware implementation is compared to the traditional impedance-based OOS protection methods. The results confirm that the proposed algorithm detects OOS conditions faster and more reliably than the traditional impedance-based solutions.Intelligent Electrical Power Grid

Out-of-Step Protection Based on Discrete Angle Derivatives

This paper presents an out-of-step protection algorithm based on angle derivatives, which makes use of wide-area measurements and can be applied on arbitrary tie-lines in electrical power systems. The developed algorithm uses PMU measurements that are taken at both ends of a transmission line. Based on the changes of the electrical quantities in the power system, the algorithm detects unstable system conditions. Thus, the developed solution is settingless and can be easily applied where an out-of-step condition is expected. The concept is deployed by using an industrial controller and tested by conducting numerous hardware-in-the-loop simulations. Additionally, recorded data from actual out-of-step events in the Icelandic power system are used to validate the developed algorithm. The performance of the implemented method is compared against the traditional impedance-based out-of-step protection methods. The results confirm that the proposed algorithm detects out-of-step conditions more reliably and faster than the traditional impedance-based solutions.Intelligent Electrical Power Grid