Calculation of the effects of short-circuit currents / Short-circuit current capability of air insulated substations

VUM calculates the thermal and mechanical effects of short-circuit currents on rigid and flexible conductors. We verify that permissible mechanical loads on equipment are not exceeded. In case permissible loads are exceeded, we develop corrective measures. VUM partners with structural engineers to review supporting structures and foundations in substations and delivers cost efficient solutions for strengthening substations in case of rising stresses caused by higher short-circuit currents, changing environmental conditions or new requirements.

Tensile forces of flexible conductors are often unknown and a main input parameter for the calculation of short-circuit forces. VUM has developed a computer program that allows the calculation of static tensile forces with virtually no restrictions.

Our services

• Local survey and creation of fact finding documentation (including a 3D terrestrial laser scan and additional on-site measurements in case no or insufficient documentation is available)
• Calculation/verification of static tensile forces of flexible conductors (catenary modelling and verification)
• Evaluating air insulated substations according to EN 61936-1 (high-voltage substations), EN 60865-1 (effect of short-circuit currents) and EN 62305-1 (lightning protection)
• Calculation of the thermal and mechanical effects of short-circuit currents according to EN 60865-1
• Assessment of support structures and foundations (with structural engineers)
• Confirmation of short-circuit capability of substations
• Development of solutions for reducing loads, reinforcing structures or other methods to reach the desired short-circuit capability

The sample images below show a flexible conductor over a transformer with a complex catenary shape (framed in orange) – picture 1. The catenaries are distorted to highlight the sag – picture 2. The modelled catenary and the curve recorded during a 3D terrestrial laser scan coincide perfectly, confirming the tensile force calculation results – picture 3.