SAI3880D发电机保护测控装置报价 免费咨询
价格：面议
2.3.2 medium strengthUnder normal test conditions, the device can withstand the frequency of 50Hz, voltage 2000V lasted 1 minutes of power frequency voltage withstand test without breakdown flashover and component damage. During the test, the other circuit is connected to the ground with the other circuit when the voltage is applied.
2.3.3 impulse voltageIn the normal test atmospheric conditions, device power input circuit, the AC input circuit, output contact circuit and loop between, can withstand the 50s of the standard lightning wave short-time impulse voltage test, open test voltage 5kV.
2.3.4 resistance to damp heat resistance
The device can withstand the damp heat test specified in the twenty-first chapter of the GB7261. The highest temperature test + 40 DEG C, maximum relative humidity of 95%, the test time for 48 hours, each cycle lasted 24 hours of cyclic damp heat test, at the end of the test within 2 hours before according to the requirement 2.3.1, measure the circuits between the conductive circuit foreign Lufei charged metal part and the shell, electrical contact between the insulation resistance is not less than 1.5m ohm, medium compressive strength of not less than 75% of the 2.3.2 provisions of the dielectric strength test voltage amplitude.
1)the maximum phase current of a side is less than 20% of the rated current, it is not sentenced to the side;
2)2) the maximum value of the phase current is greater than 120% of the rated current of the side;
3)3) served as the start of one side of the current than before the start of the increase.In the case of the above three conditions are not satisfied, such as one side at the same time meet the following conditions, then sentenced to CT break:
1)only one phase current is zero;
2) the remaining two phase currents are equal before starting the current.
3.3.2 differential current limit alarmIf the difference is greater than 15% of the rated current, after more than 10s discriminant, issued a warning signal. Differential current limit, but not locked differential protection. The function and the monitoring function of the AC sampling circuit of the protection device
3.4 loss of magnetic protection
Generator loss of excitation protection for generator excitation current abnormal decrease or disappear completely lost magnetic fault protection, by the generator stator impedance as the main criterion, combined with low voltage and generator excitation system low voltage as auxiliary criterion, and have TV disconnection locking function, TV break send alarm signal.
Its action logic is as follows:
1)under the time limit: when the three-phase current is greater than the lower limit of the value of any phase, but not meet the anti time limit start value, press the lower limit delay action on the alarm signal;
2) inverse time: when the three-phase current any phase current is larger than the inverse time starting value, according to the inverse time lag action equation I2-1 t is greater than or equal to K acts, type: I for the generator current standard? Value, K - generator stator winding allows thermal time constant.
3) the upper bound limit: when the three-phase current is greater than the upper limit value, the time limit is delayed by the time limit.
3.8 transverse differential protection
Generator transverse differential protection is usually used for the reaction of generator stator winding inter turn short circuit and a parallel windings open welding, protection from the generator neutral point between two branch imbalance fundamental current, but current is greater than fixed value setting delay action on the alarm or trip.
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