Oct 2013
Electricity Transmission
Control and Protection Challenges In Future Converter Dominated Power Systems
Oct 2013
Oct 2016
National Grid Electricity System Operator and National Grid Electricity Transmission
Jiebei Zhu
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Network Innovation Allowance
Protection and Control Systems
The project will address several inter-linked issues, including: power system characteristics and performance (“system strength”) under high penetrations of converter-interfaced sources and HVDC links; investigation of potential future problems under such scenarios; development of solutions for control and protection of such radically-changed power networks. Recent experience and extrapolations from the Irish Power system has highlighted the presence of a “75% barrier” in terms of level of converter-interfaced generation penetration. The innovation outputs are expected to explore key factors towards enabling raising the barriers up to 90%.

The innovation outputs are expected to cover following aspects:

  1. a)  Environmental & Strategic: to facilitate greater percentage of renewable power generation in GB power system.

  2. b)  Reliability: to ensure stable operation with different generation mixes, and fit for purpose transmission protection functions into the low carbon future.

  3. c)  Connection: to contribute to avoid block on renewable connections, to avoid a hard limit on renewable power development from a system technical point of view.

  4. d)  Commercial: to contribute to avoid constraining renewable power development in the low carbon future and reduce cost from billions to lower hundreds of millions of pounds per year in constrains due to system technical reasons. 

The project’s success can be measured against the following specific deliverables:

  1. Representative and validated models of VSC and LCC converters suitable both for system stability (e.g. first swing stability) and protection performance analysis.

  2. Establish confident model and studies of GB system with up to 75% NSG, applying NGET’s proposed means of improving frequency stability (optimised synthetic inertia & fast response) and steady state voltage support (in regions with absence of generation in merit)

  3. Describe key limiting factors of operation with even higher percentage NSG beyond 75%, such as:

  • Synchronising torque inadequacy.

  • LCC-HVDC converter commutation.

  • Protection reinforcement for transmission system.

  • Quality of Supply