METHOD OF SHORT CIRCUIT CURRENT LIMITATION IN MAIN Russian patent published in 2008 - IPC H01F29/14 

FIELD: electricity.

SUBSTANCE: in method of short circuit current limitation in main, in which electric reactor is used as current limiting device serially connected in main and controlled by means of magnetisation, in case of every change of main load current reactor magnetisation current is regulated until mode of full period saturation is achieved, at that minimum magnetisation current is limited down to 10% from current of full-period mode at nominal current of main load. After short circuit has occurred in the main, reactor magnetisation is changed to the value that corresponds to the mode of standardised current of long-term short circuit. At that inductances of reactor are preset based on the following conditions: L_res≤ΔU/(ωI_nom) and L_0.5>√2U_nomK_spec/(√3ωI_{spec. stand.}), where L_res - inductance of reactor full period saturation mode, L_0.5 - inductance of reactor half-period saturation mode, U_nom - nominal standard linear main voltage, ΔU%=100%×ΔU/(U_nom/√3) - standard loss of voltage in reactor in percents from nominal phase voltage of the main, ΔU - standard loss of voltage in reactor, I_nom - nominal main current, I_{spec. stand.} - standardised surge short circuit current, K_surge=I_{spec. stand}(√2I_{sc des.}) - surge coefficient of short circuit current, I_{sc des.} - active value of standardized current of long-term short circuit, ω - angular frequency.

EFFECT: reduction of voltage loss in reactor in load modes, reduction of distortions in current and voltage of electric main, control and expansion of limiting range of surge and long-term short circuit current, reduction of losses in control winding.

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