The Hokkaido Electric Power Company (Japanese: 北海道電力株式会社, Hokkaidō Denryoku Kabushiki-gaisha) (TYO: 9509), or Hokuden (ほくでん) for short, is the monopoly electric company of Hokkaidō, Japan. It is also known as Dōden and HEPCO. The company is traded on the Tokyo Stock Exchange (first section), Osaka Securities Exchange (first section), and Sapporo Securities Exchange.According to the company profile, during fiscal 2011 (i.e. 1 April 2010 to 31 March 2011), 26% of the electricity generated was from nuclear, 31% from coal, 15% from hydro, 8% from oil and 2% from 'new energy' sources.Hokkaido only has one nuclear power station, the Tomari Nuclear Power Plant.
New Hokkaido-Honshu HVDC link, which started commissioning between Hokkaido island and Honshu island on March 2019, was constructed mainly for stability in Hokkaido AC system. This link also has several functions with advantage of MMC-VSC including a black start function, and was verified these functions in effect thorough the commissioning test. About 3-years operation, this HVDC system achieved high reliability and contributing to Hokkaido AC system.
In recent years, penetration of renewable energy such as wind power generation has been increasing as measures against the global environmental problems. However, the system stability can be deteriorated when many such power supplies are introduced into the power systems. When a network fault such as a three-line-to-ground fault occurs in the grid with wind farms introduced, wind farms near the fault may be disconnected from the grid due to the voltage sag and then the grid system can be unstable. Under such a background, this paper proposes a new method for enhancing power system stability which is based on a cooperative virtual synchronous generator control between Adjustable Speed Synchronous Condenser (ASSC) and LFC (Load Frequency Control) hydro power plant.
In recent years, renewable energy has attracted attention as a measure against global environmental problems, and along with that, the penetration of inverter based power sources has been increasing. However, since there is no inertial force in the inverter based power supply, if the penetration is expanded, the inertial force of the entire power system will decrease and thus the stability may decrease. Therefore, a new virtual inertia control method using an adjustable speed synchronous condenser (ASSC) is proposed in this paper. The proposed virtual inertia control method, which is designed based on the Fuzzy Logic theory can contribute to prevent the decrease of the inertial force of the power system. It can improve the stability of the power system when the Squirrel Cage Induction Generator (SCIG) based Wind Farm (WF) trips. Performance of the proposed system is evaluated by using a model system consisting of conventional Synchronous Generators (SGs), ASSC and WF. From the analysis results, it can be confirmed that the proposed method improves the stability of the system.
Penetration of renewable energy sources, such as wind power generation and PV power generation, into the power systems has been increasing significantly. Especially, wind power generation has attracted attention due to their superior characteristics such as low cost and high energy conversion efficiency. However, the power system including large-scale wind farm (WF) can become unstable during a fault condition because WF can be decoupled due to the instantaneous voltage drop in accordance with the grid code of Fault Ride Through (FRT) requirement. This paper proposes a new two-step control strategy using High Voltage Direct Current (HVDC) interconnection line. The proposed system controls the active power and the reactive power delivered to the grid from the HVDC interconnection line during a fault condition. The effectiveness of the proposed method is confirmed by simulation analyses on PSCAD/EMTDC software.
