Introduction: ENW have secured LCNF funding a project that will trial the use of tap changing at a number of primary substations. The purpose of the trial is to establish the degree to which voltage can be either increased or decreased to provide demand increase/decrease to manage DNO network constraints. In addition staggered tap changes will be trailed to establish what scale of reactive power absorption or injection can be provided. The main focus of the trial is to evaluate degree to which primary substations can be used in this novel way without causing a noticeable impact on electricity consumers.

From a NGET perspective, the effect that these actions have on existing Transmission assets and controls must be understood in order to:

• Ensure that no adverse impact occurs on the Transmission protection and control systems

• Conversely to ensure that existing controls do not immediately counter act the intention of the trial,

• To understand the implications of the trial on Transmission asset life on Transmission asset capacity requirements, e.g. transformer capacity and shunt reactors and MSC’s for reactive power control.

Objectives:

The objectives of the project include:

• The avoidance of any negative effects on Transmission protection and control systems,
• The prevention of counter action of the Transmission controls during the project’s trials,
• Generate key learning relating to the asset capability of the Transmission systems and potential implications from the trials,
• To evaluate the technical and commercial viability of the potential ancilliary services being trialled under ENW's CLASS project

Expected Benefits:

The project will generate key learning relating to the innovative use of dynamic voltage regulation for demand response and potential to provide better value for money delivery of network services. Furthermore the project will develop an understanding of the impact of and on existing TO assets which will establish the potential for future implementation.