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  • Questions asked at the knowledge sharing event on Orkney in September 2013

    We set up a 'graffiti board' for delegates to post questions not covered during discussions. Here are the questions, complete with answers from tutors.

    Any generators/communities looking to increase load and match generation?
    We are willing to explore how we can facilitate initiatives by communities and other stakeholders in this area.
    Are network losses considered when making the business case for ANM?
    No, as they are addressed through other Ofgem mechanisms.
    Are you confident that the ANM system has had sufficient buy in from National Grid?
    This system is a distribution only system therefore there has been no involvement with National Grid. 
    Does it raise network risk?
    No, as it operates within the design capabilities of the network components and if it does fail then it fails safe. Thus ensuring that the network isn't stressed beyond its capabilities.
    Does modelling curtailment get easier once the ANM system is implemented?
    We are currently reviewing the curtailment assessments we initially made against the true curtailment that has been experienced by the individual ANM generators.  Once that review has been completed, we will be aware how accurate the initial assessments were.  We will also have the opportunity to update the generator characteristics, alter appropriate demand profiles and amend the amount of firm micro generation that has connected since the initial assessments were made.
    Have stakeholders been approached to undertake strategic reinforcement?
    No, but some stakeholders have approached SSEPD to ask what options there may be for reducing their experienced curtailment.
    How are the curtailments figures calculated?

    Data used

    • Demand profiles for each primary substation.
    • Generation profiles broken into wind or marine.
    • Principles of access to understand generator output (LIFO stack).

    Method

    For each 30 min period, the power flow at each constraint point is calculated, using the above data, to understand the impact on individual generators. 

    How has the ANM improved security of supply?
    Prior to ANM, if the control room needed to stop generators exporting to the network they would trip their metering circuit breakers, which would result in the site supplies being interrupted. The ANM system can issue the generators with a zero set point rather than tripping the circuit breaker. This ensures that the site supply is maintained whilst ensuring security of the network.
    How would state estimation help ANM?
    It would help ANM as it would allow a better understanding of what the network is doing in general rather than just in specific parts.  It would also allow the identification of bad data from physical measurements that could then be resolved.
    Is ANM a permanent solution?
    Yes, it can be. ANM can be used as a temporary solution whilst reinforcement comes along - or as a permanent solution to overcome a constraint that isn't economical to overcome.
    Is the ANM system of equal security to SCADA?
    ANM has a higher level of security as it has dual redundancy architecture to ensure that individual component failures don't cause significant issues. In addition to the dual redundancy, the ANM system also implements a fail safe rational. This ensures that if the system does fail then the network won't be stressed beyond its capabilities.
    Is there an impact on the balancing of the network when curtailing the wind turbines?
    No, the ANM system doesn't adversely affect system balance.
    Is there any HV imbalance on the Orkney network due to the single phase LV generator and demand loads?
    As per SSEPD demand connection procedures we aim to balance demand customers across the network. With generation customers this is more difficult to complete as this work generally happens behind the demand & FITs meter. The only way we are able to understand if this was an issue is via the analysis of fault records on Orkney. This shows that there is currently not a specific problem.
    What about a contingency fund for future deployments of ANM to cover unaccounted for issues?
    We believe this would be seen as 'investment ahead of need' and is not possible under the current charging mechanisms. Generators that are connected through ANM are charged a pro-rata amount for O&M of the system.
    What has been the impact on the final customer?
    Existing load and generator customers are unaffected by this technology. New generation customers connecting through the ANM system have been provided with improved access to our distribution networks.
    What is BaU?
    Business as usual i.e. integrated into our normal business activity.
    What is state estimation?
    State estimation is where you take a small number of physical measurements from the network and combine these with other indications such that by using this information and complex power system equations, you can then work out what the power flows are on the rest of the network.
    What is state estimation?
    State estimation is where you take a small number of physical measurements from the network and combine these with other indications such that by using this information and complex power system equations, you can then work out what the power flows are on the rest of the network.
    What is the generators stakeholders’ future vision of Orkney?
    Their ultimate desire is to have unrestricted access to the network.
    What is the ideal time scale for issuing set points?
    We issue a set point every second to the generator controller from Kirkwall Power Station. This was how the system was set up at the beginning and this approach has been validated through operation since 2009.
    When will you bring switchable demand into the ANM?
    We are willing to explore how we can facilitate initiatives by communities and other stakeholders in this area. 
    Why was a new platform developed rather than extending ENMACs functionality?
    We considered ENMAC SCADA DMS. However we decided we wanted to explore the use of distributed real time deterministic platform.
    Would generators move to standard connections if the constraints were removed?
    No, they would stay as they are. They could apply to move on to a 'firm' connection if they wished.