Thermal Parameters of BCT
Thermal Resistance and Impedance
The thermal resistance data and the thermal impedance curve provided are for one thyristor half, considering both thyristors are in operation, as in applications like SVC or soft starters. The thermal values for operating with only one thyristor half (as in a DC-drive) will be slightly reduced due to radial heat spreading. Ongoing studies are expected to result in new data sheet revisions that include two thermal resistance figures: one for both thyristor halves operating and one for only one thyristor half operating.
Application Examples
4.2 Application Examples
The BCT, developed as a complement to the standard PCT product range of ABB Semiconductors, aims to reduce costs and enhance competitiveness in applications where the common encapsulation of two antiparallel thyristors provides advantages. Three application examples illustrate the benefits of using BCT compared to a standard PCT solution:
4.2.1 Static VAr Compensation (SVC)
Overview:
- Static VAr Compensation (SVC) is employed for efficient power transmission, compensating reactive power to maintain a power factor close to unity on the transmission line.
- Components: Capacitors, inductors, and thyristor stacks are used in SVC installations. Thyristor stacks consist of series-connected thyristors with additional components for voltage stress reduction during turn-off.
Advantages of BCT in SVC:
- Reduced Components:
- BCTs enable current control in both directions, requiring only one stack per phase.
- Mechanical parts (heat sinks, insulators, clamps) and some electrical components are needed only once per phase, reducing the required number of components.
- Cost and Footprint Reduction:
- Depending on the system solution, the reduction in electrical and mechanical components ranges from 10% to 30%.
- Significant impact on cost and footprint.
- Enhanced Competitiveness:
- Enables SVC manufacturers to substantially improve product competitiveness.
These advantages, coupled with the increased reliability of BCTs and their comparable manufacturing process to standard PCTs, make BCTs a favorable choice for applications like Static VAr Compensation.