Energy storage to deal with commutation failure

What happens after commutation failure?

After commutation failure occurs, the DC voltage drops rapidly and the DC current increases sharply, causing a serious impact on the system, or even leading to transmission power interruption , . With the increase of HVDC transmission projects, the supporting capacity of receiving end power grid decreases .

Can a generator support a commutation failure?

Most of the existing power compensation equipment can only compensate reactive power , , and the generator which can support active power has slow response speed, so it is difficult to provide effective transient support in a short time scale to promote system power recovery and mitigate commutation failure.

Does coordinated power control of EES reduce commutation failure?

Compared with EES off or single power control of EES, coordinated power control of EES has better mitigation effect on SCFs. Coordinated power control of EES can suppress commutation failures within two times in different HVDC systems, different fault types and different fault degrees, which can effectively avoid blocking of DC system.

What is commutation failure in HVDC?

Commutation failure (CF) is one of the most common issues in HVDC transmission systems. CFs will directly cause a sudden increase in DC current and a sharp decrease in DC voltage. It is precisely because of the larger transmission capacity of UHVDC, the risk of DC pole blocking is increased due to the CFs of its converter station .

How commutation failure is influenced by AC system strength?

The commutation failure is also influenced by the AC system’s strength. The higher is the AC system’s strength, lesser will be the chances of commutation failure in a converter station and vice versa. In a single infeed LCC–HVDC system, a higher short circuit ratio (SCR) of the AC system results in lower commutation failure.

Does setting increase commutation failure resistance?

Therefore, by increasing the setting value, the commutation failure resistance can be improved to a certain extent. However, the increase of γ setting value will lead to a decrease of system transmission capacity and the increase of converter reactive power consumption, which will worsen the economy .