Grid frequency deviation response control system and method

A frequency adjustment method based on a new energy support machine and an energy storage apparatus, wherein

• the new energy support machine is connected to a power grid at a new energy grid connection point, and
• the energy storage apparatus is connected to the power grid at the new energy grid connection point;
• and
• wherein the new energy grid comprises at least one wind turbine;
• wherein the new energy support machine comprises:
• a main transformer, an excitation transformer, a doubly-fed asynchronous generator and a frequency converter;
• wherein the new energy support machine is configured to, when a system frequency of the power grid fluctuates, provide support to the power grid by injecting energy into the power grid to adjust the system frequency,
• wherein the method comprises:
• obtaining a deviation value of the system frequency when the system frequency of the power grid fluctuates;
• determining, according to the deviation value of the system frequency, a frequency adjustment scheme for at least one of the new energy support machine or the energy storage apparatus;
• and
• generating, according to the frequency adjustment scheme, a frequency adjustment instruction for at least one of the new energy support machine or the energy storage apparatus, such that at least one of the new energy support machine or the energy storage apparatus executes a corresponding frequency adjustment instruction to adjust the system frequency,
• wherein determining, according to the deviation value of the system frequency, a frequency adjustment scheme for at least one of the new energy support machine or the energy storage apparatus comprises:
• determining whether an absolute value of the deviation value of the system frequency is greater than a first frequency control threshold, and determining whether the absolute value of the deviation value of the system frequency is less than a second frequency control threshold, wherein the first frequency control threshold is a positive value, and the second frequency control threshold is a positive value greater than the first frequency control threshold,
• determining a first frequency adjustment scheme when it is determined that the absolute value of the deviation value of the system frequency is not greater than the first frequency control threshold, wherein the first frequency adjustment scheme comprises controlling the new energy support machine to be connected into the power grid to perform frequency adjustment;
• and
• determining a second frequency adjustment scheme when it is determined that the absolute value of the deviation value of the system frequency is greater than the first frequency control threshold and less than the second frequency control threshold, wherein the second frequency adjustment scheme comprises controlling the new energy support machine to be connected into the power grid to perform the frequency adjustment and controlling the energy storage apparatus to be connected into the power grid to perform the frequency adjustment,
• wherein controlling the new energy support machine to be connected into the power grid to perform the frequency adjustment comprises:
• when the system frequency decreases due to an increase in load or a decrease in power generation in the power grid, decreasing a rotational speed of a rotor of the doubly-fed asynchronous generator of the new energy support machine to make decreased kinetic energy of the doubly-fed asynchronous generator to be injected into the power grid;
• and
• when the system frequency increases due to a decrease in the load or an increase in the power generation in the power grid, increasing the rotational speed of the rotor of the doubly-fed asynchronous generator of the new energy support machine to make surplus electric energy of the power grid to be stored as kinetic energy of a stator of the doubly-fed asynchronous generator,
• wherein controlling the energy storage apparatus to be connected into the power grid to perform the frequency adjustment comprises:
• when the system frequency decreases due to the increase in the load or the decrease in the power generation in the power grid, decreasing a state of charge (SOC) of the energy storage apparatus to make decreased electrical energy of the energy storage apparatus to be injected into the power grid;
• and
• when the system frequency increases due to the decrease in the load or the increase in the power generation in the power grid, increasing the SOC of the energy storage apparatus to make the surplus electric energy of the power grid to be stored as electric energy of the energy storage apparatus.