Protective Voltage and Protective Current VS Operating Voltage

protective voltage and protective current

1. Dentinations of protective voltage and protective current?

The protective voltage and protective current come from the voltage transformer and current transformer on the grid side, respectively.

The protective voltage and protective current serve as measurement signals to detect the real-time operating status of the grid.

2. How do the protective voltage and protective current work?

The measurement signals are fed into the connected relay protection device or the built-in protection unit of the intelligent circuit breaker. This device determines whether a grid fault has occurred based on the set protection settings.

operating voltage

1. What is operating voltage?

Operating voltage refers to an independent control power supply, typically derived from a DC panel or AC control power supply.

The operating voltage provides operating energy, powering the circuit breaker's opening and closing coils.

2. How does the operating voltage work?

When the protective device issues an "open" or "close" command, the operating voltage is connected to the corresponding electromagnetic coil, generating electromagnetic force that drives the circuit breaker's operating mechanism to complete a mechanical action, thereby opening or closing the main circuit.

relationship

The logical relationship between protective voltage, protective current, and operating voltage:

Detection Decision Execution

* First Detection

The voltage transformer and current transformer continuously monitor the grid's protective voltage and current, scale them down to standard signals (e.g., 100V, 5A/1A), and transmit them to the protection device.

* Second Decision

The relay within the protection device compares the received signal with the preset protection settings. There are several possible scenarios for judgment.

Overcurrent protection: If the monitored protective current exceeds the overcurrent setting and persists for a set time, the fault is an overload or short circuit.

Undervoltage protection: If the monitored protective voltage is less than the undervoltage setting and persists for a period of time, the fault is a severe system voltage drop.

Other protections: These include overvoltage and zero-sequence current (ground fault) protection.

* Finally Execution

Once the protection device detects a fault, it immediately outputs a trip signal. This signal applies the operating voltage to the closing coil, driving the mechanism to complete closing.

conclusion

Protective voltage, protective current, and operating voltage the three interact with each other.

The protection voltage and protection current are like "sensory signals".

After being analyzed by the protection device, a command is sent in the event of a fault to control the operating voltage to drive the circuit breaker to open or close, thereby ensuring the safety of the AC power grid.