Power conversion device and estimation device

A power conversion device included in a self-excited DC power transmission system connected to an AC system, the power conversion device comprising:

• a self-excited converter to perform power conversion between the AC system and a DC system;
• and
• a control device to control operation of the self-excited converter, wherein
• the control device includes a storage to store first vibration information and a first control parameter of the self-excited converter in association with each other for each of a plurality of pieces of first vibration information,
• the first vibration information includes a first vibration component included in an AC voltage of the AC system,
• the first control parameter associated with the first vibration information is a parameter preventing the first vibration component, and
• the control device includes
• a vibration detector to detect a vibration component of an AC voltage of the AC system,
• a determination unit to determine whether first similar vibration information similar to first detected vibration information including the vibration component of the AC voltage of the detected AC system exists in the plurality of pieces of first vibration information stored in the storage,
• a setting unit to set the first control parameter associated with the first similar vibration information as a new control parameter of the self-excited converter when the first similar vibration information exists, wherein
• the vibration detector further detects a vibration component of a DC current of the DC system,
• the storage further stores a second vibration information and a second control parameter of the self-excited converter in association with each other for each of a plurality of pieces of second vibration information,
• the second vibration information includes a second vibration component included in the DC current of the DC system,
• the second control parameter associated with the second vibration information is a parameter preventing the second vibration component,
• the determination unit further determines whether second similar vibration information similar to second detected vibration information including the vibration component of the DC current of the DC system exists in the plurality of pieces of second vibration information stored in the storage, and
• the setting unit sets the second control parameter associated with the second similar vibration information as a new second control parameter of the self-excited converter when the second similar vibration information exists.