Energy Storage System (ESS) is a system that can store energy and power supply, with smooth transition, peak fill, FM and other functions. Can make solar energy, wind power generation smooth output, reduce its randomness, intermittent, volatility to the power grid and the user's impact; through the valley period of time charging, Energy Storage Systems peak price discharge can reduce the user's electricity costs; When the island can run to ensure that the user uninterrupted power supply.
Energy storage system is the core composition of micro-network, often with photovoltaic, wind power and other use together. Because the battery energy storage technology is relatively mature, large capacity, safe and reliable, low noise, environmental adaptability, easy installation, etc., so the energy storage system commonly used batteries to store electricity, the current energy storage system mainly by the energy storage unit and monitoring and (BA), battery management system (BMS), energy storage converter (PCS), etc .; Energy Storage Systems monitoring and scheduling management unit, including the central control system (MGCC), energy management system (ATM), energy management system (EMS) and so on.
Key Technologies of Energy Storage System
The energy storage system technology mainly includes the control of the energy storage converter, the management of the energy storage battery, Energy Storage Systems and the monitoring and scheduling management unit to the system energy reasonable dispatch.
Converter control strategy
Energy storage converter, also known as power conversion system (PCS), is the energy storage unit in the energy storage unit, in the monitoring and scheduling system deployment, the implementation of effective and safe storage and discharge management. At present, the commonly used converter control strategy has PQ control, VF control, droop control, Energy Storage Systems virtual synchronous machine control four ways.
(1) PQ control
PQ control is a constant active and reactive power control, control the energy output of the energy converter and reactive power equal to its reference power. PQ control is the most commonly used control of new energy and network, Energy Storage Systems only in the energy storage system grid mode can be used
The energy storage system can provide high quality power and reliable service for the transmission and distribution network. However, high capital costs and regulatory constraints tend to limit the profitability of energy storage systems.
Due to the distance, remote areas to upgrade the power grid line of expenditure may be very large. In addition, such communities often suffer from power outages. Energy storage system can not only relieve power grid pressure, but also as a remote area of the backup power supply.
The flexibility of the energy storage system can be embodied in many ways. This part of the capacity can provide a variety of services to enhance the power response speed, but also in the grid to complete the upgrade after the flexible move to other places in need. Energy Storage Systems Germany has been the energy storage system as a temporary solution for the lack of capacity of the grid line situation.
In order to reduce access to the grid, intermittent renewable energy capacity must have short-term frequency and voltage control, as well as long-term energy supply time-shift capability. For this reason, some renewable energy developers have begun to increase their storage capacity in their own power generation system.
Government policies can reduce the cost of energy storage systems to fossil fuels through subsidies or more direct mandatory procurement. Multiple cities and state-owned power grid operators are also actively developing energy storage capacity to explore the value of energy storage systems.