With the continuous development and application of renewable energy, the demand for energy storage systems in the industrial and commercial sectors is also increasing. Energy storage systems can effectively balance power supply and demand, improve energy utilization efficiency, reduce energy costs for enterprises, and provide stable and reliable power support for industrial and commercial users. This article will analyze the design process of energy storage system grid connection scheme based on actual project cases.
1. Principles of Scheme Design
The design of industrial and commercial energy storage systems is a crucial step in the implementation of energy storage projects, with the key being to ensure the safety, stability, and efficiency of the system. The main design principles are as follows:
01
Determine the access capacity of the energy storage system
Firstly, it is necessary to conduct a comprehensive energy demand analysis of the enterprise, understand key information such as the transformer situation, electricity consumption characteristics, load curve, and peak valley price difference, in order to determine the appropriate energy storage capacity and output power. At the same time, it is necessary to consider the scalability of the system and reserve space for possible future expansion. In the planning process, we also need to consider the economy of the system, by configuring reasonable energy storage capacity, striving to meet user needs while reducing system investment and maintenance costs.
02
Coordination and cooperation between energy storage and the power grid or other energy sources
Energy storage systems can serve as a powerful supplement to the power grid and operate independently, providing power support when needed. It can also be coupled and connected with photovoltaic, wind power, etc. Therefore, in the design of the connection, we need to consider factors such as the voltage level and capacity of the power grid or photovoltaic, to ensure that the energy storage system can seamlessly integrate with multiple energy sources and achieve bidirectional flow of energy.
03
Security design
The safety design of industrial and commercial energy storage systems includes electrical safety, fire safety, lightning protection safety, and other aspects. In the design of access, we need to choose suitable energy storage devices, develop a reasonable electrical layout, and set effective protection measures to ensure the safe operation of the system. At the same time, we also need to conduct regular security checks and maintenance of the system to promptly identify and address potential security risks.
04
Control strategy design
Energy storage systems involve many application scenarios in actual operation, and control strategy design is an indispensable part of energy storage systems in actual operation, aiming to improve system efficiency, stability, and reliability. For example, high/low pressure side anti backflow, demand control, coordinated operation control of photovoltaic storage, peak valley arbitrage, dynamic capacity expansion, and so on.
By installing intelligent monitoring devices and connecting them to the EMS control system, key parameters such as the operation status, power information, and temperature data of the energy storage system can be monitored in real time. Through data analysis, the system's operation strategy can be optimized to improve its efficiency. In addition, remote monitoring and scheduling of energy storage systems can be achieved through remote control systems, improving the management level and response speed of the system.
2. Design Case Analysis
Taking a 500KW/1045KWh energy storage system as an example, the existing transformer in the park is 1600KVA. The maximum load of the park throughout the year is around 900KW, and the minimum load is around 400KW. The installed photovoltaic capacity is 330KW, and we plan to add a 500KW/1045KWh energy storage system.
01
Site selection for safe energy storage locations
The selection of the location for energy storage installation is an important step in the preliminary investigation of the project, which requires comprehensive consideration of multiple factors. Firstly, the main source of revenue for energy storage comes from the peak valley price difference. It should be connected to transformers with heavy loads or high volatility in the park to maximize the peak shaving and valley filling effect of the energy storage system. It is generally recommended to install near the power distribution room to save on the cost of connecting cables.
Secondly, the site selection should meet the requirements of geological and climatic conditions. A single energy storage cabinet generally weighs over 2.5 tons, and the equipment has certain requirements for the stability of the foundation and climatic conditions. When selecting a site, it is necessary to avoid areas with unstable geological conditions, prone to natural disasters, flooded areas, as well as areas with fire exits and dense personnel.
02
Design of energy storage system access
This project adopts low voltage 400V grid connection and is connected to the existing 1600KVA transformer low voltage busbar in the feeder cabinet. The newly added energy storage grid connected cabinet is placed together with the existing photovoltaic grid connected cabinet, and the photovoltaic storage is coupled on the AC side together. The incoming end of the newly added energy storage grid connected cabinet is introduced from the outdoor energy storage combiner cabinet, and the outgoing end is connected to the low-voltage busbar for load use. The access diagram is as follows:
03
Installation design of metering meters
Due to the fact that the photovoltaic system has been built and put into operation for a long time, considering the need for coordinated operation and control strategies for the new energy storage system without affecting the original photovoltaic system, the design aims to achieve monitoring of the entire power generation and consumption chain by adding metering devices on the mains side, photovoltaic side, and energy storage side. The metering equipment will be uniformly connected to the EMS system to upload monitoring data.
By adding energy storage side metering meters, photovoltaic side metering meters, and total anti backflow metering meters. The bidirectional electricity meter for energy storage billing is installed in the energy storage combiner cabinet to measure the charging and discharging information of the energy storage system and settle electricity bills.
The photovoltaic metering meter is installed in the photovoltaic grid connected metering cabinet to monitor the total photovoltaic output (this method does not require the addition of a 485 cable to the inverter end, does not require communication with the inverter, and does not restrict photovoltaic power generation).
The anti backflow low-voltage meter is installed on the low-voltage bus side of the municipal power supply, used to detect backflow conditions and calculate load electricity consumption (projects with high-voltage anti backflow requirements can be replaced with high-voltage side metering).
04
Basic installation design of energy storage system
Installation area of energy storage cabinet: A single energy storage cabinet is 1.2 meters wide, 1.4 meters deep, and 2.35 meters high, occupying an area of approximately 1.68 square meters. When excavating a foundation pit, it is necessary to compact the plain soil and reinforce the foundation for wet and loose materials The foundation construction site should be selected at the highest point of the surrounding terrain to prevent water accumulation and damage.
The installation pier shall be made of concrete, and the bottom load of the installation pier foundation shall not be less than 2000kg/square meter. The basic surface should be leveled with a ruler to ensure levelness; The bottom plane of the foundation should be inclined towards both sides to ensure drainage.
05
System operation strategy design
Guriwatt's self-developed EMS control system supports multiple control strategies and is suitable for various usage scenarios. By presetting strategy parameters and collecting real-time data on photovoltaic, energy storage, power grid, load, etc., coordinated control and issuance of multiple operating mode strategies are carried out. This project controls the coordinated output of photovoltaic and energy storage through EMS, which can maximize the economic benefits of electricity consumption in the park.
06
Main project quantities
| Project name | Quantity of work |
| Preliminary plan | On site investigation, collection of necessary information for energy storage systems, determination of preliminary plans and investment returns, and preparation for filing |
| Design drawings | Provide a detailed plan, design electrical diagrams, access diagrams, and construction drawings for the energy storage system |
| Civil engineering part | Remove existing debris, clear corridors, energy storage cabinet foundations, and cable trench construction |
| Electrical part | Wiring for energy storage equipment, monitoring communication, metering meters and CT, and grid connection points for energy storage cabinets |
| Equipment installation | Installation of energy storage cabinets, fixed and safe fences, sunshades, etc |
| Equipment debugging | Check wiring, power on debugging of equipment, and data debugging of monitoring platform |
| Operation training | Training on the daily use and operation of the equipment will be conducted |
Summary
As an important direction in the energy field, industrial and commercial energy storage has broad application prospects and development space. I hope that through the above introduction of industrial and commercial energy storage design schemes, everyone can further understand industrial and commercial energy storage systems, which will be helpful for the design of industrial and commercial energy storage projects.