The sinusoidal voltage of rated frequency applied to the secondary terminals of current transformer, with other winding being open circuited, which when increased by 10% cause the exiting current to increase 50%. C400 protection current transformer assuming i nom 5a v volt 0,01 0,1 1 10 excitation currentamp 400. Ct application guide ge grid solutions online store. Full descriptions of the relay characteristics are found in the 489 manual. Knee point voltage of current transformer this is the significance of saturation level of a ct core mainly used for protection purposes. Knee point voltage of current transformer electrical. How to calculate the knee point voltage of a current. When the core reaches maximum flux density, it is fully saturated and there are no more magnets remaining to change this causes direction. At the kneepoint the voltage across the secondary tends to remain constant whereas the current continues to rise.
What is the secondary limiting voltage of a current. Knee point voltage calculation of ct free download as excel spreadsheet. The knee point determines the saturation voltage of a. Definition of the ct kneepoint voltage iec 600441 class px formerly british standard bs3938. Guide for calculation of ct for generator differential protection. Knee point voltage of current transformer ps class. Voltage v s, in turn, generates current i s through the connected circuit. Pdf the impact of currenttransformer saturation on. The saturation point is at a voltage 10 to 20% greater than the true kneepoint of. Knee point voltage calculation pd49jo89p8n9 documents and e. This means that an increase in 50% current will lead to just an increase in 10% voltage. Rudolf class x ct with knee point voltage of 1b5v is suitable to be use in thls application. Please help me how to calculate the same its very argent. What is the secondary limiting voltage of a current transformer.
This concept is the one used for testing the kneepoint in current transformers with the pte100c. The saturation point is at a voltage 10 to 20% greater than the true kneepoint. What is the difference between ct secondary limiting voltage and knee point voltage. How to calculate knee point voltage of current transformer. Dear all,waht is knee point voltage of ps class ct,when i am order for 40001a ps class ct,vendor ask me for the knee point voltage of the same. Therefore, the cts according to ansiieee must have a kneepoint voltage. Knee point voltage can be calculated using formula. Ct knee point voltage calculation transformer volt scribd. Ct knee point voltage calculation free download as pdf file. The impact of currenttransformer saturation on transformerdifferential protection article pdf available in ieee transactions on power delivery 303. The knee point is defined as the voltage at which a 10% increase in applied voltage increases the magnetizing current.