Control System And Experiments On A New Type Of Saturated Iron Core

Along with the expanding power network, the fault current has increased greatly. It will bring hidden troubles to the security, stability, credibility of the power system. Conventional current limiters gradually show their limitation and can't fit the request of high power quality. The fault current limiting technology has become a hotspot of fault protects research.On the background of developed superconductivity, superconducting fault current limiter (SFCL) is the most promising device in power grid. When the short current occurs, the traditional saturated iron core High Temperature Superconducting Fault Current Limiter (HTSFCL) doesn't cut off the dc excitation, the effect is inconspicuous and superconducting excitation wedding must endure inductive high voltage, In this case, dc power supply is difficulty to maintain constant current. In this paper, we suggest a new type SFCL and emphases its control system, Active Saturated Iron Core HTSFCL, which is when detected the fault happened, cut off the dc circuit as quickly as possible in safety. When the grid is in normal operation, the dc current is adjusted to make the iron cores in deeply saturated so that the voltage drops on the ac windings are low. When a fault comes, break off the dc current, inductive voltages appear, limit the fault current. In our approach, the dc circuit brealdng strategy was adopted. High temperature superconductor silver sheathed Bi-2223 tape was used for the dc coil. Accurate fault detection and a reliable high speed dc circuit breaker are critically important. We used a High Voltage Insulated Gate Bipolar Transistor (HVIGBT) as the circuit breaking element.Based on this, a 380V/50A SFCL system and short current test platform are developed, on the platform of LabVIEW, which consist of voltage sensors, current sensors, a 16 precision data acquire card and back-to-back connected thyristors and so on.Different kinds of short circuits are conducted and the theoretical predictions and simulations are validated by the experiment results, which lay a sound foundation for the 35kV/1.5kA HTSFCL system that will be installed to a power grid in PUJI station of YUNNAN province.