Loss of load cost, energy not severed, net loss and loss of load duration, are considered when deciding which load should be curtailed.

Balance weight set free fall emergency braking device, which can realize auto control load loss protection, when the wellhead end accidental loss of load, balance weight free fall.

This paper is concerned with the simplified steady state conditions of the system based on DC load-flow, which implies the reliability indices calculated are the measures about static loss of load.