Fast Transfer Switch (FTS)

Fast Transfer Switch (FTS)

^ü   FTS is used to obtain the minimum time of switch between two sources of power. This can be achieved by analyzing the phase shift between sine waves of two power sources.

^ü   FTS permits to control zero phase shifts between input signals of power sources. These signals are passed through A/D converter and then to PLB form the control signal for solid state relay to secure the moment of zero phase shifts between input signals.

^ü   It increases the speed of connecting the load to the power sources with optimal parameters.

1. Performance of Fast Transfer Switches:

^ü   Under normal condition the voltage and frequency of power sources1 and power sources2 are inside suitable range of tolerance and load get power from PS1 through closed SSR1.

^ü   ZD1 and ZD2 form menders from input sine wave signal. Generate the control signal from PLB the unit of ADC converter input voltage from PS1, PS2.

^ü   In PLB, the measured the value with reference minimum and maximum value of input output voltage are compared.

^ü   If any measured value of signal from PS1 is out of tolerance then should be formed the signal to the switch the load to PS2.

^ü   The same procedure is used t control the frequency of input signal and phase shift between PS1 and PS2.

^ü   If any parameter of signal power source is changed then ADC would form the value of code and this value goes to PLB.

^ü   After comparing the measurement value of input voltage with minimum and maximum accepted values.

^ü   If the signal will be formed to switch off the SSR1 means signal to switch on the SSR2 will form is according with synchronism and phase shift between signals from PS1 and PS2.

^ü   In general any case failure of one commercial source of power, the switch transfers the load to another source in very short time.

^ü   It is also achieve by synchronized phase control of signal from both power sources. It makes possible to choose the power source during the time interval less than 1ms.