EPN RDP: Walpole
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Regional Development Plan Walpole GSP (EPN) Planner: Peter Rye Version: 1.0 Date: 24/06/2013 UK Power Networks (Operations) Limited. Page 1 of 34 Registered in England and Wales. Regional Development Plan Walpole GSP (excluding Peterborough) Contents 1 EXECUTIVE SUMMARY .................................................................................................................................. 3 1.1 SUMMARY OF ISSUES ADDRESSED ........................................................................................................................ 3 1.2 INVESTMENT PROFILE ........................................................................................................................................ 4 2 NETWORK CONFIGURATION .......................................................................................................................... 6 2.1 EXISTING NETWORK .......................................................................................................................................... 6 2.2 NETWORK CHANGES IN PROGRESS ........................................................................................................................ 6 3 NETWORK DEVELOPMENT CONSIDERATIONS .................................................................................................. 7 3.1 DEVELOPMENT AREAS ....................................................................................................................................... 7 3.2 ASSET REPLACEMENT ........................................................................................................................................ 7 3.3 SECURITY OF SUPPLY ANALYSIS ............................................................................................................................ 9 3.4 OPERATIONAL & TECHNICAL RESTRICTIONS ........................................................................................................... 10 3.5 NATIONAL GRID ............................................................................................................................................. 12 4 RECOMMENDED STRATEGY ......................................................................................................................... 12 4.1 DESCRIPTION ................................................................................................................................................ 12 4.2 FINANCIAL APPRAISAL AND BENEFITS .................................................................................................................. 15 5 REJECTED STRATEGIES ................................................................................................................................ 15 6 REFERENCES ............................................................................................................................................. 15 6.1 APPENDICES ................................................................................................................................................. 15 6.2 DOCUMENT HISTORY ...................................................................................................................................... 15 7 DOCUMENT SIGN OFF ................................................................................................................................. 16 Regional Development Plan Template v1.1 Page 2 of 34 Regional Development Plan Walpole GSP (excluding Peterborough) 1 Executive Summary This Regional Development Plan (RDP) reviews the UK Power Networks (UKPN) EPN HV and EHV network supplied from Walpole Grid Supply Point (GSP) with RDP 3 the exception of the area in the vicinity of RDP 1 Peterborough that is covered by RDP02. RDP 4 The western part of the area is supplied via two grid RDP 2 substations (Walsoken and March) that are supplied from one of the dual circuit 132kV lines between RDP 10 RDP 9 Walpole and Peterborough. The eastern part of the RDP 6 RDP 12 RDP 5 area is supplied via four grid substations (Kings Lynn, Kings Lynn South, Hempton and Swaffham). The latter three are supplied by a dual circuit 132kV line from RDP 11 Kings Lynn Power Station, which connects back to RDP 8 RDP 7 Walpole GSP by two dual circuit 132kV lines, one with RDP 18 RDP 17 a tee connection to Kings Lynn Grid and the other with RDP 13 a tee connection to the ‘Palm Paper’ factory. RDP 14 RDP RDP 16 RDP 20 This latter load is probably the most significant in this 15 RDP 19 area, with a maximum demand of 60MVA. Their future plans include a doubling of capacity (timescale as yet Figure 1 – Area covered by the RDP indeterminate and dependent upon market demand) and a 162MW on-site generation station for which they have recently initiated a planning application. Kings Lynn Power Station is presently the most significant generator in the area with a capacity of 400MW, although this is presently mothballed. The owners have permission for a ‘B’ station (980MW) and National Grid are presently progressing a planning enquiry for a 400kV connection for this. The area is also seeing a large volume of applications for generation connections. Historically these were mainly wind generators and were centred on the area between March and Peterborough, and connections have been restricted for some time due to the limited ‘reverse power’ capability at March Grid. This area was therefore chosen as the trial area for the ‘Flexible Plug & Play’ project which is intended to facilitate the connection of embedded generation. However, requests are now biased towards solar farms and have a much wider spread, with many requests in the eastern and northern parts of the area. At the time of writing there are 12 customers who have accepted connection offers for a total of 147MW (54MW Solar, 25MW EfW & 68MW wind). As a result of this the 33kV network around Swaffham & Hempton Grid Substations is now ‘saturated’ and a number of quotations have had to be withdrawn as further generation can now only be connected via constrained connections. We are presently processing another 17 ‘formal’ applications totalling 185MW, although it is not anticipated that many of these will be viable due to the restrictions mentioned above. 1.1 Summary of issues addressed The main issues addressed by this RDP are: Reinforcement requirements at individual substations 33kV network issues 132kV n-2 issues Generation effects The main elements of this RDP are as follow: Carry out reinforcement works at individual primary substations as required by load growth Replace the 132/33kV transformers at March Grid with 90MVA units Install a second 132/33kV transformer and additional 33kV switchgear at Kings Lynn South Grid Regional Development Plan Template v1.1 Page 3 of 34 Regional Development Plan Walpole GSP (excluding Peterborough) Source a remotely controllable pole mounted 33kV switch to enable the auto-changeover schemes at the single transformer primary substations to be reinstated Undertake modifications to the interconnected 33kV network to reduce the potential for ‘cascade failures’ to occur in the event of a 132kV n-2 outage 1.2 Investment Profile The Figure below provides the projected expenditure profile for reinforcement and asset replacement projects (LRE and NLRE) in this RDP for both DPCR5 and ED1. This information is taken from the NAMP version 05-06-2013. DPCR5 2015 2016 2017 2018 2019 2020 2021 2022 RIIO-ED1 IDP 2013-15 /2016 /2017 /2018 /2019 /2020 /2021 /2022 /2023 Total LRE £5.3m £4.7m £5.2m £4.3m £2.6m £2.1m £3.2m £6.2m £11.2m £39.5m NLRE £0.1m £0.7m £1.5m £2.2m £1.2m £0.4m £1.7m £2.3m £2.1m £12.1m TOTAL £5.4m £5.5m £6.7m £6.4m £3.8m £2.5m £5.0m £8.5m £13.3m £51.6m Table 1. LRE and NLRE expenditure profile Output Measures The figure below provides the expected Load Indices (LI) for all substations covered in this RDP at the end of the ED1 period (2022/23). Substations with a projected load index of LI4 and LI5 will be specifically targeted for improvement and are detailed in this document, with the resulting improvement also shown in the figure below. Figure 2. 2022/23 Load Indices with and without interventions The figures below provides the projected health index of various assets covered in this RDP at the beginning and end of ED1, with and without interventions as defined in the NAMP under asset replacement. Regional Development Plan Template v1.1 Page 4 of 34 Regional Development Plan Walpole GSP (excluding Peterborough) Figure 3. Health Indices by asset category Scenarios considered Demand growth from Planning Load Estimates (PLE’s) up to 2023. Major Generation sites disconnected. Compliance with P2/6 Standard for Security of Supply and operational flexibility of the 132kV network. Modifications to National Grid network Interconnection to other DNO RDP Dependencies and Interactions The interaction with Peterborough RDP has been considered. Regional Development Plan Template v1.1 Page 5 of 34 Regional Development Plan Walpole GSP (excluding Peterborough) 2 Network configuration 2.1 Existing Network The network considered by this document is supplied from the National Grid 400/132kV substation at Walpole. The network comprises 6 grid substations and 31 primary substations. A geographical diagram of the network is shown in Appendix A and single line diagrams of the network are shown in Appendix B. The main features of the network are: A 132kV double circuit overhead line from Walpole to West March, feeding March 132/33kV Grid Substation (2 x 45MVA transformers) and Walsoken 132/33kV Grid Substation (2 x 90MVA transformers).