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Peak shaving and valley filling energy storage project

Peak shaving and valley filling energy storage projects

This article will introduce Grevault to design industrial and commercial energy storage peak-shaving and valley-filling projects for customers.

In the power system, the energy storage power station can be compared to a reservoir, which stores the surplus water during the low power consumption period and uses it again during the peak power consumption period.

Among industrial users, it can perform peak-valley adjustment to to alleviate the burden on the transformer during the peak period of electricity consumption in summer, and to obtain certain income by using the peak-to-valley power difference.

In addition, for users with important loads, the Grevault industrial and commercial energy storage system can be used as a backup power supply to ensure the continuity of power supply for important loads.

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    Project overview

    There is a huge difference in the load of two transformers in a large commercial project in a certain area during operating hours and non-operating hours. And the local peak and valley electricity prices vary greatly. Now consider adding a Grevault industrial and commercial energy storage system to the low-voltage side of the transformer.

    Store electricity during the “valley” period of electricity and discharge it during the “peak” period of electricity. In this way, the power peak load can be cut and the valley can be filled, and the user-side demand response can be adjusted.

    The Grevault industrial and commercial energy storage system can not only reduce the peak load of the grid, but also contribute to the safe operation of the grid, and can also generate huge economic benefits.

    Project overview

    Grevault industrial and commercial energy storage system operation mode

    The local peak and valley electricity price charging standards are as follows:

    Time zone A B C D E F
    Daily time (hour) 0-8 8-12 12-15 15-17 17-21 21-24
    Time interval (hours) 8 4 2 3 4 3
    Peak/Valley Valley Peak Flat Flat Peak Flat
    Selling electricity price (RMB/kwh) 0.322 1.112 0.667 0.667 1.112 0.667

    The working mode of the energy storage power station can be basically determined by the electricity price as follows:

    Time zone A B C D E F
    Daily time (hour) 0-8 8-12 12-15 15-17 17-21 21-24
    Operating mode Charge Discharge Stop working Stop working Discharge Stop working

    The peak and valley Grevault industrial and commercial energy storage system completes the charge and discharge cycle every day. That is to complete the process of storing electricity in the low electricity price area and discharging in the high electricity price area, the electricity purchased during the 0-8 o’clock period needs to meet the electricity consumption from 8-12 o’clock and 17-21 o’clock. The installed power of the Grevault industrial and commercial energy storage system is 250kw, and the installed capacity is 2MWH.

    Battery selection

    This design uses lithium iron phosphate battery, which has high energy density and small footprint. And the production process adopts fully automatic equipment, and the product consistency is good. The consistency of battery cells is an important guarantee for the safe and stable operation of energy storage power stations. The specific parameters of the battery are shown in the table below:

    Industrial and commercial energy storage battery Specification
    Cell type Lifepo4
    Rated Capacity 280ah
    Nominal voltage 3.2v

    PCS selection

    A power storage converter (PCS) is a device connected between the battery system and the grid in an electrochemical energy storage system to realize bidirectional conversion of electric energy. PCS is composed of DC/AC bidirectional converter, control unit and so on.

    The PCS controller receives the background control command through communication, and controls the converter to charge or discharge the battery according to the sign and size of the power command, so as to realize the adjustment of the active power and reactive power of the grid.PCS

    At the same time, the PCS can communicate with the EMS through the CAN interface to obtain the status information of the battery pack, which can realize the protective charging and discharging of the battery and ensure the safe operation of the battery.

    PCS is the core equipment of the energy storage system. Grevault industrial and commercial energy storage systems use high-quality PCS to ensure the safety of the project.

    According to the situation of this project, a power converter of 250kW is adopted.

    Battery Management System

    The protection and monitoring functions of the battery system are realized by the BMS battery management system. The BMS system of the battery system is divided into three levels of network architecture:

    (1) Battery management detection module CCM: Monitor the voltage and temperature of 12S single cells, and transmit the above information to BMU in real time through daisy chain communication, which can control the voltage balance of single cells.

    (2) Battery management slave control unit BMU: Statistically organizes the voltage and temperature data collected by multiple CCMs under management, and transmits the above information to the BCU in real time through the CAN protocol, and can control the CCM to perform equalization according to the equalization command issued by the BCU.

    (3) Battery management main control BCU: Detect the total voltage and current of the entire battery pack, collect information from lower-level BMUs, estimate the remaining capacity and health status of the battery in real time, and transmit the above information to the EMS in real time through the CAN protocol. Control the opening and closing of the relay, and alarm and protect the battery pack.

    Grevault industrial and commercial energy storage has three layers of protection BMS, which is safe and reliable.

    Grevault industrial and commercial energy storage overall design

    According to the area reserved for the project, this scheme adopts 3 energy storage prefabricated cabins, of which 2 are energy storage battery cabins and 1 is a PCS cabin.

    The total installed capacity of the project is 2MWh, which is divided into two energy storage branches. Each energy storage branch consists of a 250kW energy storage rectifier, a 1MWh energy storage battery and an energy management system. The two energy storage branches are respectively connected to the 400V low-voltage busbar side of the 1# and 2# transformers in the power distribution room.

    The energy storage system consists of energy storage batteries, energy storage converters (PCS), battery management systems (BMS), and management systems (EMS). The energy storage battery completes the DC/AC conversion through the PCS and connects to the AC bus to realize energy storage and release.Grevault industrial and commercial energy storage overall design

    The PCS controls the energy storage battery to perform charging and discharging actions: in the charging state, the PCS acts as a rectifier to convert the electric energy from AC to DC and stores it in the energy storage battery; in the discharging state, the PCS acts as an inverter to convert the electric energy stored in the energy storage battery from The DC is changed to AC to support the operation of related loads.

    The BMS can monitor the voltage, current and temperature of the energy storage battery in real time. By transmitting key information to the EMS, the EMS coordinates and manages the charging and discharging process of the energy storage system to avoid problems such as overvoltage, undervoltage and overcurrent. It has charge and discharge balance management function.

    Summary

    According to the owner’s electricity consumption situation, the energy storage system of the project discharges during the peak period of electricity consumption and charges during the off-peak period, so as to solve the customer’s off-peak electricity consumption.

    At the same time realize peak shaving and valley filling, earning the difference between peak and valley electricity consumption, thereby reducing customer consumption. electricity cost. According to the calculation of the daily peak-shaving and valley-filling income of energy storage and the annual accumulated income, it has a good income performance.

    Project Consulting

    If you are interested in learning more about GreVault’s program, please complete and submit this form.

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