Development of an Inverter with Synchronization and Inertia Forces that can be Integrated with Conventional Generators - Enabling Increased Introduction of Renewable Energy into Microgrids -
PACIFIC CONSULTANTS CO., LTD.
Pacific Power Co., Ltd.
PACIFIC CONSULTANTS CO., LTD. (Address: Chiyoda-ku, Tokyo; President and Representative Director: Tomoyuki SHIGENAGA) and Pacific Power Co., Ltd. in PACIFIC CONSULTANTS GROUP (Address: Chiyoda-ku, Tokyo; President and Representative Director: Michiko GOUZU), a member of the PACIFIC CONSULTANTS GROUP (hereinafter referred to as our GROUP), have been working on the "Development of Grid-Connected Inverter Control Technology Based on the Virtual Synchronous Generator Concept for Utilizing Variable renewable energy" (hereinafter referred to as "This Development") in collaboration with Environmental Energy Technology Research Inc., Toshiba Corp., and National Institute of Advanced Industrial Science and Technology (AIST)) as part of the Ministry of the Environment's Incentive Technology Development and Demonstration Project for Strengthening CO2 Emissions Reduction Measures from FY2019 to FY2021 (JPN). As a result, we are pleased to announce the development of the "Grid Forming Inverter (hereinafter referred to as GFM)," an inverter with synchronizing force and inertia force that can be operated together with a synchronous generator within a microgrid, and the microgrid control system "Grid Editor."
Introduction of the Developed System
In order to realize a low-carbon society, it is necessary to promote the use of renewable energy power sources such as solar and wind power instead of thermal power generation, which rely on fossil fuels. However, in order to introduce a large number of these power sources, whose output changes irregularly depending on the weather, in a microgrid, energy management for stable power system frequency and efficient power use is a challenge. In the demonstration project associated with this development, we developed a new inverter control technology that can maintain the same synchronization force and inertial effect as conventional thermal power generators (synchronous generators), and prototyped a GFM with a voltage control method that is actually compatible with renewable energy power sources and energy storage devices to verify its function. In addition, we proceeded with development with off-grid (microgrids and remote islands that are independent of the power grids of general power transmission and distribution companies) in mind, especially at a renewable energy early stage, and developed not only the inverter but also the "Grid Editor" control technology and system for the entire off-grid that introduced it.
What was Confirmed through the Demonstration Project
In this demonstration project, a small-scale simulated microgrid (70% variable renewable energy ratio, installed capacity basis) that implemented these systems was constructed at Fukushima Renewable Energy Center of the National Institute of Advanced Industrial Science and Technology, and it was demonstrated that it can actually be operated under various conditions. For the first time in the world, it was confirmed that the GFM combined with a storage battery exerts synchronizing and inertial forces in response to fluctuations in the grid frequency as expected, contributing to the stabilization of the microgrid, by operating a synchronous generator with an internal combustion engine in parallel with the GFM in an off-grid environment. In addition, the frequency deviation was confirmed to be within ±0.5Hz with a staying rate of more than 90% over long-term operation, confirming generally stable operation.
Furthermore, for those microgrids that are connected to the grid during normal times, it is possible to further increase profitability by aggregating their adjustment power and providing it to the wholesale electricity market and supply-demand balancing market together with general distributed energy resources.
The system developed and demonstrated this time will be provided primarily to municipal new power companies in which Pacific Power Co., Ltd. participates, and will also be provided to microgrids nation-wide as a series of service packages including GFM. It is particularly expected to be introduced in regional microgrid businesses and power distribution businesses developed in areas that are pioneering decarbonization efforts.
PACIFIC CONSULTANTS GROUP will continue to contribute to the revitalization and development of cities through its local energy business.