CT Metered

Current Transformer (CT) metering is used for larger electricity supplies where the current is too high for a standard meter. CTs step down the current to a measurable level while maintaining accurate proportional readings. This type of metering is standard for supplies above 70kW.

What makes CT metering different:

• Can measure very high currents (hundreds or thousands of amps)
• Provides half-hourly (HH) consumption data
• Required for Profile Classes 05-08 and mandatory above 100kW
• Typically has both import and (potentially) export capability
• Records kWh, kVA, and kVArh for complete consumption picture

CT metering and charges: Supplies with CT metering typically face:

• Site Specific tariffs (LV_SS, LVS_SS, HV_SS) rather than Aggregated
• Capacity charges based on agreed kVA
• Potential reactive power charges if power factor is poor
• Capacity Market obligations
• More complex DUoS calculations

Why CT metering matters for validation: CT metered supplies have actual half-hourly data, meaning:

• Exact Red/Amber/Green consumption split is known
• No profile estimation needed
• More precise validation possible
• But also more ways for billing errors to occur

CT ratio: The CT ratio (e.g., 200:5) indicates how the measured current relates to actual current. Bills should reflect actual consumption, not CT secondary values.