Class trials

CLASS trials

To demonstrate the CLASS (Customer Load Active System Services) approach and to understand if customers are aware of any effect on their electricity supply, we ran four trials on 60 primary substations during 2014. This represents 17% of our network and around 485,000 customers.

The trials

Trial 1: Voltage increment and decrement over one year
Trial 2: Voltage decrement to achieve a demand response at times of system peak
Trial 3: Voltage decrement to provide a fast frequency response
Trial 4: Reactive power absorption to redress high network voltages

Choosing the CLASS trial area

We developed a methodology for choosing the 60 primary substations which serve the trial area. This ensured that the trial area was representative of our geographic area and our different customers.

Monitoring the CLASS trial area

As part of the trial we collected and analysed a varied and significant amount of data so that we could share our findings with the rest of the industry.

This included information on voltage and power quality so that we could quantify the effects of the CLASS trial on the regional and national electricity networks and our service to customers.

We carefully selected a number of locations across our network to install monitoring equipment to enable us to gather the data we needed.