1. PV impacts on Suburban Networks Philip Bale Western Power Distribution Innovation and Low Carbon Networks Engineer 01332 827448/07525241432 pbale@westernpower.co.uk LCNF Annual Conference - Cardiff Thursday 25 th October 2012 Understanding Networks – an early presentation of data

2. PV impacts on Suburban Networks Connection of Photo Voltaic Panels The Feed in Tariff resulted in a dramatic increase in the number of distribution network connected Solar PV panels. G83 connections This was particularly prevalent in particular suburban networks, expedited by Local Authorities installing generation on their housing stock Concern over the connection of PV generation to the LV network. The LV network has historically operated with very limited network monitoring and operates based on well known diversified load profiles. Significant amounts of PV in one area resulted in a increased number of assumptions being made. Number of connections

3. Monitoring in Nottingham Aspley and Broxtowe – EDMI MK6E meters Meadows – EMDI MK6E meters and portable sub.net monitors Analysis - Does a high concentration of Solar PV have an impact on: Network Voltage tolerances Thermal Limits Voltage Fluctuations and Flicker Voltage and Current imbalance Voltage and Current harmonics Power Factor Network Monitoring

4. Network Voltage tolerances Blue – LV busbar voltage Frinton Road Aspley, Red – 11kV Tx1 & Tx2 voltage Cinderhill Primary substation Voltage Voltage (kV) Time

5. Thermal Limits & Current Imbalance Tunstall Crescent - Three Phase current over a two week period Average current during the two week period L1 – 68.96A L2 – 99.12A L3 – 125.89A Voltage Time

6. Voltage and Current harmonics Voltage and current waveforms The effect of current harmonics on the waveform

7. Frinton Road Tunstal Crescent Hilcot Drive Lindbridge Road Voltage Total Harmonic Distortion Total Harmonic Voltage distortions – one week period of sites in Aspley and Broxtowe 8 th - 14 th October 2012 Voltage Time

8. Contribution of Solar PV for demand Measured current - Blue Solar radiation - Red Estimated demand being masked by generation - Green Time

9. PV’s in Suburbia Early Learning 1.Voltage profile at the substation 2.Current imbalance of network feeders 3.Current and Voltage Harmonics – including waveforms 4.Voltage harmonics – Total Harmonic Distortion 5.Contribution from Solar PV to demand