Complete the following sentence using one of the phrases from the box below.
To ensure safety and compatibility with domestic appliances, the extremely high potential difference used in the long-distance transmission lines of the national grid is reduced to a lower voltage at local substations using _________.
28 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid, covering 13.2.1 Transformers and induction, 13.2.2 The transformer turns-ratio equation, 13.2.3 The National Grid, 13.2.4 The transformer power equation, and 13.2.5 Advantages of high-voltage transmission. Each one has a worked solution and a mark scheme showing where the marks go.