1. Purpose:
SQP-2/S digital underfrequency relay is used as a frequency reduction response element in power grid lines such as load shedding and automatic disconnection according to frequency.

2. Characteristics of SQP-2/S Digital Under Frequency Relay
2.1 Use digital switch direct reading for frequency setting, without the need for formula conversion;
2.2 All digital switches for action frequency, locking frequency, delay frequency, and △ t are installed on the panel for easy setting operation;
2.3 During operation, the digital display shows the normal system frequency. When the relay is activated, the instantaneous system frequency is displayed and locked. Only after pressing the reset button can the normal system frequency be restored.

3. Main technical data
3.1 Frequency setting range: 45-49.99Hz;
3.2 Frequency setting error: not greater than ± 0.015Hz;
3.3 Under frequency action return coefficient not greater than 1.002;
3.4 The return time for low-frequency actions shall not exceed 60ms;
3.5 Under frequency action delay setting range: 0.08-99.9s, with a step difference of 0.01s;
The monitoring level frequency remains constant at 51Hz;
3.7 Locking level frequency setting range: 45-49.99Hz, with a step difference of 0.01Hz;
3.8 Setting range of slip locking circuit: 1-2Hz/s;
3.9 The power at rated voltage and rated frequency shall not exceed 4VA;
3.10 Low voltage lockout setting range: 55-60V.

SQP-2/S digital underfrequency relay