4.2.4.3 Grid

Spec reference: 4.2.4 (subtopic).

What you need to know

• Grid
• The National Grid is a system of cables and transformers. They transfer electrical power from the
• power station to where it is needed. Power stations are able to change the amount of electricity that
• is produced to meet the demands. For example, more energy may be needed in the evenings when
• people come home from work or school. Electricity is transferred at a low current, but a high voltage
• so less energy is being lost as it travels through the cables.
• Step-up transformers – increase the voltage
• as the electricity flows through the cables.

Self-assessment (checklist)

• I can name the parts that make up the National Grid.
• I can describe the purpose of the National Grid.
• I can explain the purpose of step-up transformers.
• I can explain the purpose of step-down transformers.
• I can explain why the National Grid system is an efficient

Key steps (method)

• Identify what the question is testing and use the correct equation/definition.
• Show substitutions and units clearly.

Common mistakes

• Unit conversions, rearranging errors, or quoting a law without applying it.