PowerGrid ESS

# PowerGrid ESS

Document reference: PowerGrid-INF-01_v3

Disclaimer
Information in this document is for general purposes only. While we make every effort to ensure accuracy, we make no guarantees and reserves the right to change details without notice. For the latest information, please contact us or visit our website.

Introduction

We provide two family of subsystems for grid applications:

• PowerGrid 3x subsystems are built with 2, 3 or 4 units of our 1.6MW / 3MWh BESS container delivering up to 6.4MW and 12MWh per subsystem
• PowerGrid 5x subsystems are built with 2 or 4 units of our 2.58MW / 5MWh BESS container delivering 5MW/10MWh or 10MW/20MWh per subsystem. This can be configured as a 2 hour or 3 hour or 4 hour battery storage.

PowerGrid 3X

The PowerGrid 3X BESS subsystems is built for 1.6MW to 6.4MW and 3.08MWh to 12.3MWh ESS blocks and includes:

• up to FOUR units of 20C1600K BESS containers each with 8 independent battery strings with dedicated Inverters.
• ONE unit of MV container with 5250 kVA or 6600 kVA transformer and LV and MV switchgear and metering. Can be configured for 20kV or 30-35kV installations.
• ONE set of network switch and subsystem controller for SCADA, PPC and EMS services.
• All power and data cables for the subsystem to the MV container and control cabinet.
• A power output to site substation, a Modbus TCP interface for BESS monitoring and PPC and EMS services for each of the units of 20C1600K BESS containers.

Depending on the power and capacity required, we can provide the optimum BESS configuration.

PowerGrid 5X

The PowerGrid 5X BESS subsystem is built for 2.5MW to 10MW and 5MWh to 20MWh ESS blocks and includes:

• up to FOUR units of 20C2500K BESS containers each with 12 independent battery strings with dedicated Inverters.
• ONE unit of MV container with a 5500kVA or 10000kVA transformer and LV and MV switchgear and metering. Can be configured for 20/21kV or 33/35kV installations.
• ONE set of network switch and subsystem controller for SCADA, PPC and EMS services.
• All power and data cables for the subsystem to the MV container and control cabinet.
• A power output to site substation, a Modbus TCP interface for BESS monitoring and PPC and EMS services for each of the units of 20C2500K BESS containers and the MV transformer substation.

It can be configured as a 2 hour, 3 hour or 4 hour battery by adjusting the MV transformer sizing and derating the BESS container power via our PPC controller.

20C1600K AC BESS

Architecture

The 20C1600K BESS container has modular architecture with:

• Liquid cooled battery packs made with LFP cells and a Battery Management Unit (BMU).
• Battery cluster / strings with a Controller (CMU).
• Separate AC/DC Inverters (PCS) for each battery string.
• Liquid temperature control system and HVAC dehumidifier.
• Firefighting system, backup power.
• BESS controller (GPC) to handle safety, automatic operation and data and control communication with external BESS and EMS SCADA

Container description

The 20C1600K system uses a customized container with a stronger load-bearing case and reinforcement steel frames in the middle while maintaining the same dimensions as a 20ft HC container.

Anti-corrosion materials are used for the paint of the container shell to improve the anti-corrosion performance of the container.

The shell interlayer is installed with 50mm thermal insulation rock wool to improve the thermal insulation performance of the system.

In the battery compartment, there are battery Strings, liquid cooling unit, air conditioners for dehumidification and cable slots, etc. Battery Strings are installed on both sides of the battery container, lighting, thermal sensors, smoke sensors, firefighting pipe and other equipment are installed above the side aisle.

In the electrical compartment, there are PCS, GPC, Firefighting Control System, power distribution system, BESS controller with 24h back up power, air conditioner and auxiliary power supply distribution system.

Independent string inverters

We use independent string inverters. Independent string inverters provide better capacity protection compared to central inverters. By comparison, with central inverters, over time, charge and discharge performance of parallel battery racks will vary due to divergences in the internal resistance of the cells.

Tests have shown that capacity loss increases by up to 2 % per year when eight racks are connected in parallel with a central inverter compared to non-parallel connections with independent inverters. Batteries connected in parallel can also lead to current loops and barrel effects due to voltage differences, resulting in a reduction in the usable capacity of the system.

Tests data also show that when two battery racks are connected in parallel to a central inverter, and the SOC differs by 8%, after a complete charge-discharge cycle, the total discharge capacity of the energy storage system with independent PCS inverters (ACDC or DCDC) is increased by up to 7%. So independent string inverters offer the best long term performance.

Specifications

AC side

DC side

General

20C1600K capacity over project life

The evaluation point is on MV transformer POC output point, considering the auxiliary electrical loss and internal consumption.

Cells are rated to 10,000 full cycles (0.5P 25°C 100% DOD) to > 70% of initial capacity. In normal operating conditions, BESS is rated at 10,000 full cycles over 12 to 15 years to > 70% of initial capacity (see below degradation curves).

Most likely scenario:

1 full cycle per day or about 365 full cycles per year over 15 years at 0.5P rate.

High usage scenario:

up to 2 full cycles per day (about 730 full cycles per year) over 15 years at 0.5P rate.

PowerGrid AC BESS efficiency

including all auxiliary power consumption

Certifications

The 20C1600K and its active components are fully certified according to UL and CE latest safety standards and thermal runaway tested as per UL9540A:

• UL9540A thermal runaway certified.
• UL1973 certified.
• IEC 62619 certified.
• CE-LVD and CE-EMC.
• UL1741, IEC 62477, EN 50549-1&-2, LVD for PCS.
• UN38.3, UN3536, etc.
• Fingrid SJV2024 certified by TUV for PCS.

20C2500K AC BESS

Architecture

The 20C2500K BESS container has modular architecture with:

• Liquid cooled battery packs made with LFP cells and a Battery Management Unit (BMU).
• Battery cluster / strings with a Controller (CMU).
• Separate AC/DC Inverters (PCS) for each battery string.
• Liquid temperature control system and HVAC dehumidifier.
• Firefighting system, backup power.
• BESS controller (GPC) to handle safety, automatic operation and data and control communication with external BESS and EMS SCADA

Container description

The 20C2500K system uses a customized container with a stronger load-bearing case and reinforcement steel frames in the middle while maintaining the same dimensions as a 20ft HC container.

Anti-corrosion materials are used for the paint of the container shell to improve the anti-corrosion performance of the container.

The shell interlayer is installed with 50mm thermal insulation rock wool to improve the thermal insulation performance of the system.

In the battery compartment, there are battery strings, liquid cooling unit, air conditioners for dehumidification and cable slots, etc. Battery Strings are installed on both sides of the battery container, lighting, thermal sensors, smoke sensors, firefighting pipe and other equipment are installed above the side aisle.

In the electrical compartment, there are PCS, GPC, Firefighting Control System, power distribution system, BESS controller with 24h back up power, air conditioner and auxiliary power supply distribution system.

Independent string inverters

We use independent string inverters. Independent string inverters provide better capacity protection compared to central inverters. By comparison, with central inverters, over time, charge and discharge performance of parallel battery racks will vary due to divergences in the internal resistance of the cells.

Tests have shown that capacity loss increases by up to 2 % per year when eight racks are connected in parallel with a central inverter compared to non-parallel connections with independent inverters. Batteries connected in parallel can also lead to current loops and barrel effects due to voltage differences, resulting in a reduction in the usable capacity of the system.

Tests data also show that when two battery racks are connected in parallel to a central inverter, and the SOC differs by 8%, after a complete charge-discharge cycle, the total discharge capacity of the energy storage system with independent PCS inverters (ACDC or DCDC) is increased by up to 7%. So independent string inverters offer the best long term performance.

Specifications

AC side

DC side

General

20C2500K capacity over project life

The evaluation point is on MV transformer POC output point, considering the auxiliary electrical loss and internal consumption.

Cells are rated to 10,000 full cycles (0.5P 25°C 100% DOD) to > 70% of initial capacity. In normal operating conditions, BESS is rated at 10,000 full cycles over 12 to 15 years to > 70% of initial capacity (see below degradation curves).

Most likely scenario:

1 full cycle per day or about 365 full cycles per year over 15 years at 0.5P rate.

High usage scenario:

up to 2 full cycles per day (about 730 full cycles per year) over 15 years at 0.5P rate.

PowerGrid AC BESS efficiency

including all auxiliary power consumption

Certifications

The 20C2500K and its active components are fully certified according to UL and CE latest safety standards and thermal runaway tested as per UL9540A:

• UL9540A thermal runaway certified.
• UL1973 certified.
• IEC 62619 certified.
• CE-LVD and CE-EMC.
• UL1741, IEC 62477, EN 50549-1&-2, LVD for PCS.
• UN38.3, UN3536, etc.
• Fingrid SJV2024 certified by TUV for PCS.

CBMV transformer blocks

Overview

CBMV transformer containers are built to specifications to connect to 1 to 4 BESS containers. It includes:

• The main transformer - three-phase double winding 10kV~35kV Oil immersed type transformer with optional integrated oil pool/recovery system.
• Switch cabinet with 4 LV Automatic circuit breakers + 1 MV Circuit breakers and Power Distribution system.
• 200kVA Auxiliary Transformer to provide auxiliary power to its controller and to the 4 BESS containers (each requiring a maximum of 44 kVA).
• Integrated Smart Energy Meter, UPS, SPD.

We provide 4 variants: 3300kVA, 5500kVA, 6600kVA and 10000kVA for 2 or 4 units of 20C1600K or 20C2500K BESS containers.

All CBMV transformers are SF6 free.

Specifications

Overview

Protection

General

Inrush current

Inrush current is the high current that a transformer draws when it is first energized. This current is caused by the sudden change in magnetic flux in the transformer's core, and is proportional to the current flowing through the primary winding of the transformer.

Transformer connection options

The CBMV6600K can be connected to either:

• two or four containers with one or two containers per transformer loop each with separate LV busbar.
• three containers with a single transformer loop and LV busbar for all containers.
  This is a special configuration available on demand.