Urban power grid transformer direct current magnetic bias suppression method

The invention discloses a urban power grid transformer direct current magnetic bias suppression method. The method specifically comprises the steps of: establishing a subway and urban power grid direct-current resistance network model based on a subway and urban power grid topological structure; calculating a main transformer neutral point current by using a node admittance method; inhibiting the main transformer neutral point current by using capacitor direct current blocking devices under the constraint condition that the amplitude of the main transformer neutral point current exceeds a threshold value; under the condition that the main transformer neutral point direct current meets a direct current magnetic bias suppression requirement, establishing a target function with the minimum installation number of the direct current blocking devices as a target, and optimizing the installation positions of the capacitor direct current blocking devices through a genetic algorithm. According to the method, distribut