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NETWORK / 9 / SEPTEMBER 2019 Phil Lawton, power systems practice manager at the Energy Systems Catapult and former future system operation manager at National Grid, looks at the key areas where the system operator and the industry could improve. Few people can have been surprised that National Grid Electricity System Operator's interim report into the low frequency incident on 9 August concluded that, in the face of a very unusual event, the networks and their protection systems worked broadly as intended. However, rather more interesting than asking whether today's rules were followed to the letter, is the question of "could we do better?" This question can be applied in at least four areas: l The current primary mechanism for controlling the frequency: part-loaded generators and battery storage. These methods both depend upon capacity that is held on standby, ready for when a fault happens. This 'loss of opportunity to maximise output' makes frequency response expensive (£132 million in 2018/19) and hence care is taken to deploy only what is needed. Conversely, if frequency response is held on the demand side, power flows normally except during a low frequency event when it reduces for a short period. Imagine a system where, when the frequency drops, EV chargers reduce their consumption, or export to the grid and electric heating/cooling responds in a progressive way by altering the set point of the thermostat without changing the consumer experience in any substantive way. If such features were designed in, the electrification of heat and transport would mean that frequency response would no longer be scarce. This would both lower the cost of operating the system and reduce the risk of the Low Frequency Demand Disconnection (LFDD) scheme operating. l Tripping of embedded generation. Over a decade after the last event caused by the near coincident loss of two generators, we have not resolved the issue of such incidents being exacerbated by the avoidable tripping of embedded generation (in this case, a very significant apparent loss of 500MW). This is a straightforward technical problem and the lack of progress represents a failure of the current change mechanisms within the industry. l The fall-back LFDD scheme. While the scheme prevented the incident from escalating, it is a blunt instrument tripping 132/33kV transformers. The current LFDD scheme was developed in the 1970s, when colour televisions and calculators were being introduced. If we move to providing much higher levels of frequency response on the demand side, the chance of the LFDD scheme operating will reduce greatly and it may be considered more fit for purpose. On the other hand, if we continue to tailor the level of frequency response to the largest loss, we should consider applying LFDD further down the system to better manage its impact. l Resilience on the customer's side of the electricity meter. It is ironic that the main disruption seems to have happened to the railways, whose main traction supplies are not subject to LFDD to try and avoid significant economic disruption. Those operating essential services, and the networks serving them, need to develop a shared understanding of the credible events that can happen to each other's systems and the associated impact on operations, both in shutting down safely and the recovery phase. There is a developing theme here of new technologies needing to be integrated with the wider power system. However, while "whole system thinking" has become something of a buzzword, the industry is not set up to support or implement it. Code Governance – the process for making and reforming the rules governing how the industry operates - is provided by multiple parties managing a series of codes including the Balancing & Settlement Code, Grid Code, Connection & Use of System Code, Distribution Code and Distribution Connection and Use of System Agreement – the list goes on. Each of these is managed by a bespoke process with different stakeholders/panel members/objectives and little coordination. While the process can deliver incremental changes to one code, it simply cannot support the timely, strategic, sector-wide changes that we will require. The key areas where changes to Code Governance will improve how the network operates, including reducing the chances of a repeat of the 9 August incident, are: l Creating a body with strategic responsibility for the whole sector, rather than a series of bodies looking after individual silos. This body would have responsibility for code changes and technical coordination. l Wider representation in the decision- making process. l Fostering a problem-solving culture, rather than an adversarial approach to whether individual changes should be implemented. l A faster, less bureaucratic process for making changes. National Grid concluded that the incident was caused by the unusual coincidence of two large plants disconnecting. A change in direction for the power industry might be driven by the coincidence of this low frequency incident and the current BEIS consultation. "The current LFDD scheme was developed in the 1970s, when colour televisions and calculators were being introduced. If we move to providing much higher levels of frequency response on the demand side, the chance of the LFDD scheme operating will reduce greatly." A change in direction