PST691U Transformer Differential Protection Device

Guodian Nanzi PST691U Transformer Differential Protection Device

I. Functions

1. Differential protection

2. Second and third harmonic restraint

3. Differential instantaneous trip protection

4. Differential current over-limit alarm

5. TA disconnection detection

6. Collection of non-electrical protection action information

7. GPS time synchronization (second pulse, minute pulse, or IRIG-B mode)

Environmental Conditions
Ambient temperature: -25℃ to +55℃;
Relative humidity: 5% to 95% (no condensation or icing inside the product);
Atmospheric pressure: 66kPa to 106kPa
Power Consumption
AC current circuit: When In=5A, ≤0.5VA per phase; when In=1A, ≤0.3VA per phase.
AC voltage circuit: At rated voltage, ≤0.5VA per phase.
DC power supply circuit: During normal operation, ≤10W; during device operation, ≤20W.
Overload Capacity
AC current circuit: 2 times rated current, continuous operation; 10 times rated current, allowed for 10s; 40 times rated current, allowed for 1s.
AC voltage circuit: 1.4 times rated voltage, continuous operation allowed.
Insulation Performance
 Insulation resistance
Under normal test atmospheric conditions, the insulation resistance between the external live circuit parts and exposed non-live metal parts and casing, as well as between electrically independent circuits, measured with a 500V megohmmeter, is not less than 100 MΩ.
 Dielectric strength
Under normal test atmospheric conditions, the device can withstand a power frequency voltage test of 50Hz for 1min without breakdown, flashover, or component damage. During the test, when voltage is applied to any tested circuit, the remaining circuits are interconnected and grounded at equal potential.
 Impulse voltage
Under normal test atmospheric conditions, the DC input circuits, AC input circuits, output contacts, and other circuits of the device can withstand a short-duration impulse voltage test with a standard lightning wave of 1.2/50µs. The open-circuit test voltage is 5kV.