Principle of operation
The ATS controller acquires the electrical parameters of the mains and standby power supply by means of sensors such as voltage transformers and current transformers. These parameters are continuously sampled and transmitted to the controller’s processing unit. For example, for voltage monitoring, it sets a normal voltage range, e.g. ±10% of the rated voltage. When the mains voltage exceeds this range, a subsequent judgement mechanism is triggered.
Based on the collected parameters, the microprocessor within the controller will make judgements based on preset rules. These rules may include factors such as the type of power failure (whether it is an instantaneous fluctuation or a long outage), the readiness of the backup power supply (e.g., whether the generator has been warmed up, started successfully, etc.), and so on. If it is determined that the primary power supply has indeed failed and the standby power supply is available, a conversion command is generated.
The changeover command drives the electric or electromagnetic operating mechanism in the automatic transfer switch. These mechanisms act quickly to switch the load connection from the mains supply to the standby supply. During the switchover process, in order to avoid problems such as short circuits caused by simultaneous connection of the two power supplies, the ATS controller strictly controls the switchover timing to ensure that the main power supply is disconnected first, and then the standby power supply is connected after a certain time interval (typically a few milliseconds to several tens of milliseconds).