With the integration of renewable energy resources as part of the net-zero transition, electricity networks will experience a loss of inertia which is well documented. This situation makes the power systems more dynamic and time constants for mitigations are getting shorter. These decreased reaction times in operation require automated systems which can tackle the higher dynamics in the grid. Wide Area Monitoring, Protection, Automation and Control (WAMPAC) schemes are one key element in this context. Wider availability of synchronized phasor data increases the observability and awareness of higher system dynamics. The phasor data and power system modelling will be used to develop a roadmap and proof of concept for advanced WAMPAC systems including optimised automated network control enacting contingency measures for power system events.
Benefits
Consumer benefits are described as part of the Cost Benefit Assessment in section 3.2.1. The assessment is based on three value levers, i.e. reduced risk of blackouts, reduced constraint cost through better system awareness and improved effectiveness of network investment. The net consumer benefit of this proposal is estimated as £1M. It is expected that funding in a future regulatory period will be required and therefore no specific additional benefits would be accrued by electricity transmission and distribution networks.
Learnings
Outcomes
Year 2024/25
Review of existing OTS and WAMS and comparison against required Design Considerations for System Integrity Protection Scheme (SIPS) and WAMPAC: In summary, the strengths of the existing OTS are found in its speed of operation as well as its simple, transparent, safe and dependable design. However, considering that both the arming and the firing of individual OTS actions may have financial and other consequences, its limitations with respect to selectivity and adaptability highlight the need to explore possible enhancements to ensure optimal performance and effective risk mitigation. Based on this assessment, two separate recommendations were made:
- Assisted arming of existing event-based OTS via online dynamic security assessment
- Response based OTS based on PMU measurements (e.g., voltage angle difference between substations)
Recommendations for further work
Year 2024/25
The project is very useful for NGET (and other organisations) in establishing the extended scope, scale and skill sets of work necessary to implement regional automation such as Wide Area Control using PMU data. Legacy operational tripping schemes are very deterministic and monitor circuit breaker or disconnector status, not the network loading or power angle. These schemes need to trip very quickly as the event has happened. WAC on the other hand looks at whether network conditions can accommodate the event and maximise availability without tripping or loss of load.
The investigation to date has established that the accuracy and detail of network models is a key element to validating the future applicability of this type of solution, in particular active control elements associated with HVDC controllers and wind farm generators.
The sharing of commercially sensitive data is a major restriction, necessitating generic models to be used. Generic models need validating and may not entirely replicate the regional interactions that are the point of interest, especially where network PMU data, along with other control measures will be used to feed the regional control schemes that is the subject of the study.
The longer term requirement for in house Real-Time Digital Simulator (RTDS) capability is also worth further investigation to test changes to wide area schemes before they go into commission and understand how components can be replaced (e.g. firmware updates or adding new circuits) minimising the down time of any service.
Lessons Learnt
The OTS protection settings are currently derived from simulations using an offline analysis tool. Since these models rely on approximations, conservative margins are typically applied to ensure reliability. However, this can limit the full utilisation of grid assets.
Dissemination
Year 2024/25
Though the project was at its early stage as at the last reporting. It has progressed since then, and there are plans to disseminate in the near future.
