Issue link: https://fhpublishing.uberflip.com/i/1218318
when considering the different types of energy generation they will be working with, and also the types of operations they will be putting the generators through, which will almost certainly exceed the design parameters of the equipment involved. "One of the main challenges is that with biomass and gas generation, for example, there's emissions legislation that we have to adhere to consist - ently – and the generators are not designed to be tested this way," says Chandler. "So, there's liaison with the Environment Agency and Natural Resources Wales etc., to keep them in the loop and make sure we stay on the right side of the law, with re - gard to those potential emissions from pushing the generators." He continues, "In terms of technical challenges, these gen - erators are not designed to do what we are going to put them through. They're designed to just effectively sit there at a nice steady load and generate power – but we're going to be asking them to be able to regulate fre - quency to compensate for when we apply blocks of demand." Other pivotal challenges for Chandler's team will include overcoming the types of prob - lems presented by the generally less-stable network environment of the small distribution power islands created in the trials – such as inertia challenges, volt - age challenges and managing system frequency – so the ability of the team to stabilise the power islands will be key. This has led Chandler's team to issue a tender out to energy technol - ogy providers to design an au- tomated control system in order to allow for optimal operation of the generators. "The theory is that loading this generator, ap - plying large blocks of demand, is very onerous on the genera- tor and might cause it to trip or damage. So, we want to be doing this in as smooth a way as possi- ble and the best way to do that is through automation. Our 'micro grid control system' tender has provided the opportunity for a number of companies to go away NETWORK / 19 / MARCH 2020 also been challenged within the scope of the Black Start project to explore the use of both syn- chronous and non-synchronous self-starting generators in the restoration process. Chandler believes both are vi- able. "A generator wouldn't nec- essarily need to be synchronous – I think certainly the conven- tional methods of self-starting generators assume a synchro- nous generator, the reason being that synchronous can regulate frequency, regulate voltage, and can effectively apply block loads and operate in a number of dif- ferent modes that are needed. "There are asynchronous gen- eration technologies out there that can potentially operate in a self-starting generator mode, but we've got none of those on the system at the moment, but we will be doing a piece of work around this involving our academic stakeholders. "A German project proved the concept and utilised a bat - tery for asynchronous self-start capability on a gas generator, and at present we've had some companies come back to us and say 'our converter could be made to offer grid-forming capability, effectively making it a self-starting generator', but we will not be testing these in our live trials as yet." To date there have been nu - merous trials around the world, testing many of the individual elements involved in the Black Start chain, but no one has actually brought all of them together into a coordinated, holistic project, which is what makes the Distributed Restart Project "so cool", says Chandler. "We're actually looking at a full-on restoration service at distribution level, bolting all these innovative ideas and pro - jects together. What we're trying to achieve has not been done before, so I genuinely believe it's a world first!" Commercial and transition agendas In terms of the commercial and procurement elements of the project, there is a lot of interest and design control systems in order to do that." Once a successful design has been put forward and awarded a contract, the project team will push forward with the build of a physical system which can be tested as a part of these live trials. "In regards to that, the initial live trials will be fairly manual type trials and fairly ba - sic – but ramping them up, with the control system, that'll be like the final piece of the jigsaw that we can start testing." Bringing DERs in from the cold One of the major challenges in making distributed Black Start a reality is overcoming the problem of cold starting remote generation assets. "When the grid goes down, there's no power for the genera - tor to effectively self-start, so it needs its own power supply on site – a backup generator to effectively jumpstart that main unit," explains Chandler. "That could be a big battery or a die- sel generator. With the live trials we're going to be hiring in some of the equipment necessary to carry out the restarts – backup generators – to act as auxiliary power supplies." Chandler and his team have "These generators are not designed to do what we are going to put them through," PETER CHANDLER, PROJECT LEAD, DISTRIBUTED RESTART from flexible demand compa- nies and DERs wanting to par- ticipate, with an eye to commer- cial benefit from the provision of Black Start services. Chandler and his team have now compiled options for the procurement and design of services, so clarity is growing as to what these commercial mod- els might entail – an essential development if distributed Black Start is ever to take up the man- tle of mainstream grid backup. Part of the work has also en- tailed consideration of potential clashes between Black Start con- tracts and the activities that the same DERs might be providing to current and future Distribu- tion System Operators (DSOs). "We're at a point now where we're taking those ideas out and sharing them with all the stakeholders, giving them the opportunity to comment, feed - back and hopefully shape new markets," says Chandler. "And yes, there is potential for clash with the DSO agenda, but we're mitigating that through our engagement with ENA networks. This whole transition to DSOs is still ongoing, so we are working with them to make sure what we propose for our Black Start DER solutions actually aligns with what they're doing." Chandler continues: "The direction of transition seems to be where a DSO can procure its own balancing services – voltage, frequency and inertia control products – and then the ESO can procure its own, also. There's already a whole host of services that the ESO currently procures and contracts with pro - viders, so all of that will start to be opened out to play as well." As this increasingly crowded landscape of flexibility and reliability services develops at a distribution and transmis - sion level, Chandler is firm that central coordination of services and prioritised availability of contracted parties will be key – and in this he sees a major ongo- ing responsibility for the ESO. As trials for Distributed Restart move forward, we will see just how tricky a task this may be.