Method for analyzing operation state of substation by combining whole grid model with local grid model

A method for analyzing an operation state of a substation by combining a whole grid model with a local grid model, comprising:

• step 1:
• performing a first load flow calculation on a provincial grid to which a ultra-high-voltage line belongs, wherein initial data of the first load flow calculation takes a grid model with E format for a national power grid dispatching control center;
• performing an equivalent transformation on the grid model;
• forming an island independently from the provincial grid to which the ultra-high-voltage line belongs;
• and performing a second load flow calculation on the island to acquire data of node voltages and line transmission power;
• step 2:
• analyzing a current carrying capacity and the node voltages based on the acquired data in the step 1 to obtain a flow characteristic of a whole grid system after an ultra-high-voltage compatibilization;
• and providing initial data for a transient simulation;
• step 3:
• establishing a local simulation model in a transient simulation software based on the provided initial data in the step 2 to analyze a primary equipment of an ultra-high-voltage substation after the ultra-high-voltage compatibilization;
• and obtaining over-voltage, over-load and breaking capability of a circuit breaker of a transformer of the ultra-high-voltage substation in various conditions through calculation;
• and
• step 4:
• controlling the ultra-high-voltage line in a steady and secure range according to the over-voltage, over-load and breaking capability of the circuit breaker of the transformer of the ultra-high-voltage substation.