The rotor low voltage action criterion equation is： Kf×Vfd/125 < (P-Pt)/866 3.5 Over load protection Generator stator winding protective reaction of load generator stator winding overload or fault caused by overcurrent caused overheating winding, discrimination protection generator winding B phase current size, when the current is higher than setting value when the delay send alarm **. 3.6 compound voltage over current protection Generator compound voltage over-current protection is as a generator of symmetric and asymmetric short-circuit fault back-up protection, protection discriminant generator three-phase current, AC phase voltage and negative sequence voltage, when any phase current is greater than the fixed value, and AC phase voltage less than fixed value or negative sequence voltage is greater than the fixed value export protection settings have two period of time delay, a movement in solution column or splitting demagnetization, off action to stop, protection can choose to take the current memory function. 3.7 inverse time overcurrent protection Generator anti time limit over current protection of the generator stator winding current size, the protection of the winding due to the current too large and lead to the stator winding overheating, the protection of the three-phase current size of the judge, from three parts: 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 **. 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 **. Its action logic is as follows: 3.10 stator overvoltage protection For generator, in particular to a hydro generator, after load rejection due to the speed control of speed control system can not keep up, is easy to appear the stator voltage exceeds the allowed range of over voltage phenomena; at this point to be equipped with over voltage protection, protection from the generator terminal voltage when any phase of more than setting value by setting the delay action to stop. 3.11 stator ground protection Generator stator grounding protection can for the generator neutral point ungrounded or via arc suppression coil grounding grounding, protection from the generator end opening of the delta winding voltage when open delta windings voltage greater than setting value by setting the exit delay. 2.2 Main technical performance Precise working range of 2.2.1 sampling circuit (10% error) Voltage: 0.4 V ~ 120V Current: 0.08In20In 2.2.2 contact capacity Signal circuit contact current carrying capacity 400VA Signal circuit contact fault arc capacity 60VA 2.2.3 tripping current Breaker trip current 0.5A~4A (order indication) The circuit breaker closing current 0.5A~4A (the order stated) 2.2.4 precision of various components Current component: <5% Voltage components: <5% Time element: 0s-1s, the error is not more than 40ms; 1s above, the error is not more than < + 2.5%; Frequency deviation: <0.02Hz
