Fig. 2: Basic principle of the gas-electric early warning system.

When a major failure occurs in the gas network, adjacent valve chambers are closed to isolate the failure, and the gas-electric early warning system starts to work. Three power generators (G0, G1, G2) are depicted to show the power generation adjustment, among which G1 and G2 are fired by the gas network. a The major failure occurs in the gas network (I), and then failure signals are sent to the GDC (II). In this case, G2 is the impacted gas turbine because its connection with the gas source is completely severed. Then, early warning indicators are calculated by the GDC and sent to the EPCC (III). b To reduce the impact of the potential failure of G2 on the power system, the EPCC formulates the proactive control strategy of the power system based on the early warning indicators (IV). The power generation of G2 is gradually reduced while that of other generators is increased to maintain the balance of the power system (V). c If a complete substitution of power generation by G2 is achieved before its inlet pressure drops to the protection threshold, the security of the power supply will not be affected (VI).