Effektberegning

Effektberegning, or power calculation, is the process of determining the power requirements or consumption for a system, building, or installation. It is used to ensure that electrical equipment, cables, and protection devices are adequately rated and that energy use is understood and optimised. The practice is applied in electrical engineering, construction, and energy management, and relies on data about loads, operating conditions and efficiency.

Key concepts include real power P, apparent power S, reactive power Q, and the power factor cosφ. Real power represents energy converted to useful work; apparent power is the product of voltage and current; reactive power arises from inductive or capacitive elements. For three-phase systems P = √3 × V_L × I × cosφ, S = √3 × V_L × I, Q = S × sinφ.

Methodology: identify all loads with rated powers, estimate operating modes and durations, apply simultaneity and diversity factors, sum to obtain necessary P and S. Assess peak versus average demand, account for inrush and voltage drop, and choose conductor sizes, protective devices, and transformers accordingly. Consider efficiency and power factor correction measures to minimise energy use and equipment size.

Applications include sizing electrical installations in buildings, machinery, renewable energy systems, and data centers. Effektberegning supports compliance with standards and safety codes, and informs decisions on equipment selection and energy management.

Limitations and uncertainties: load fluctuations, equipment aging, temperature effects, harmonics. The results are estimates and should be reviewed by qualified personnel and updated as conditions change.