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.
2.2.4 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
2.2.5 the entire set of action time (including the inherent time of the relay)
Time of motion of a fast moving segment:
1.2 times the value of the entire set of measurement, not more than 50ms
2.2.6 transient transcendence
No more than 5%
2.2.7 og measurement loop accuracy
Measurement and control device for installing special measurement sub module:
Current, voltage: 0.2
Power and electric degree: 0.5
2.3 insulation performance
2.3.1 insulation resistance
Device for charged and uncharged part and a casing and electrical contact of the circuit between the open circuit voltage of 500V megohm meter measuring the insulation resistance value, normal test atmospheric conditions, the circuits of each class of insulation resistance should not be less than 100m ohm.
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.
Three、Software function deion
3.1. differential quick break protection
When any phase difference current is greater than the value of the differential speed, the protection action is stopped. Fast removal of generators in the case of a serious fault in the area of the generator. Differential speed determine the value should be able to avoid the external fault of the maximum unbalanced current, and taking into account the current transformer saturation factor, generally take 3 to 8 times the rated current
3.2.Ratio differential protection
Using the conventional ratio differential principle, the equations of motion are as follows:
Id > Icd (Ir Ir0)
Id - Icd > Kcd ·(Ir- Ir0) (Ir ≥ Ir0)
At the same time to meet the above two equations, the ratio of the differential element action. Among them, Id for the differential current, Ir for the braking current, Kcd for
Ratio braking coefficient, Icd is the threshold value of the differential current, and Ir0 is the turning point of the current value.