Case Study: Heat Pump Disruptive Load on LV Overhead Lines
Overview
As part of the Customer-Led Network Revolution (CLNR) project, approximately 378 air source heat pump (HP) customers were recruited and monitored across three different customer trials.
Of the 378 heat pumps, the vast majority were standard domestic capacity HP units and the remaining were larger capacity HP units capable of maintaining heating during either demand side response (DSR) calls or delayed operation during time of use peak pricing, both via the means of a hot water thermal store.
This report is a case study that has taken information gathered as part of a voltage issue investigation that Northern Powergrid undertook in response to a customer reporting a voltage complaint under the Guaranteed Standards of Service – Regulation 15.
The voltage complaint was received in November 2013 from a single customer who was suffering voltage fluctuations (flicker), as a result of the operation of one of the larger HP units that had been installed in their neighbour’s adjacent property.
Both properties were electrically connected to the same part of a low-voltage rural overhead line network and were situated at the extremity of that network. The customers’ location exacerbated the effects of the HP motor characteristics, highlighting the voltage issue, which otherwise would have been difficult to detect. This is the only instance recorded on the CLNR project where the HP operation caused such a voltage issue.
This report aims to inform both DNOs and HP installers of the potential effects that could be seen by future installation of HPs on LV networks and in particular on rural LV OHL networks. The report also considers the current connections application process for HP installations and makes certain recommendations and lessons learned observations, including improving the communication of the current HP connections process.
This report did not evaluate any other installations of HPs that are currently connected to the Northern Powergrid network and has kept the identities of the customers involved anonymous.
