GB/T 34120-2017Technical specification for power conversion system of electrochemical energy storage system (English PDF)

4.1 Product classification

4.1.1 According to the connection relationship with the power grid

Power conversion systems, according to the connection relationship with the power grid, can be classified into.

-- grid-connected and grid-disconnected switching type power conversion systems;

-- grid-connected type power conversion systems;

-- grid-disconnected type power conversion systems.

4.1.2 According to the connected voltage level

Power conversion systems, according to the connected voltage level, can be classified into.

-- Class A1 power conversion system, a power conversion system applied to energy storage power stations connected to the power grid through a voltage level of 10(6) kV and above, and with an AC terminal voltage of the power conversion system not greater than 1 000 V;

-- Class A2 power conversion system, a power conversion system applied to energy storage power stations connected to the power grid through a voltage level of 10(6) kV and above, and with an AC terminal voltage of the power conversion system greater than 1 000 V;

-- Class B1 power conversion system, a power conversion system applied to connection to the distribution network through 10(6) kV;

-- Class B2 power conversion system, a power conversion system applied to connection to the distribution network through 380 V;

-- Class B3 power conversion system, a power conversion system applied to connection to the distribution network through 220 V.

4.1.3 According to installation and service environment

Power conversion systems, according to the installation and service environment, can be classified into.

-- indoor type power conversion system, a power conversion system installed inside a building or an enclosure with a protection grade of IP54 and above;

-- outdoor type power conversion system, a power conversion system with its structure completely or partially exposed outdoors.

4.1.4 According to cooling method

Power conversion systems, according to the cooling method, can be classified into.

-- natural cooling type power conversion system;

-- air cooling type power conversion system;

-- liquid cooling type power conversion system.

4.1.5 According to topology structure

Power conversion systems, according to the topology structure, can be classified into.

Example 1.

A power conversion system with a DC voltage range of 580 V ~ 1 500 V, an AC terminal rated voltage of 400 V, a rated power of 50 kW, and a single-stage conversion topology, is marked as. EES-PCS-580~1 500 V-400 V-50 kW-S-×××××.

Example 2.

A power conversion system with a DC voltage range of 350 V ~ 700 V, an AC terminal rated voltage of 800 V, a rated power of 200 kW, and a two-stage conversion topology, is marked as. EES-PCS-350~700 V-800 V-200 kW-D-×××××.

Example 3.

A power conversion system with a DC operating voltage range of 500 V ~ 1 200 V, an

AC terminal rated voltage of 10 kV, a rated power of 5 MW, and a cascaded topology, is marked as. EES-PCS-500~1 200 V-10 kV-5 MW-H-×××××.

5.1 Environmental conditions

The power conversion system shall operate normally under the following environmental conditions.

a) Temperature. -20°C ~ +40°C;

b) Relative humidity. <=95%;

c) For power conversion systems applied under high-altitude conditions above 2

000 m, comply with the relevant provisions of GB/T 20626.1;

d) For power conversion systems applied in marine climate, meet the salt spray resistance requirements.

5.2 Electrical conditions for grid-connected operation

Grid-connected and grid-disconnected switching type power conversion systems and grid-connected type power conversion systems shall operate normally under the following power grid conditions.

a) The harmonic voltage shall not exceed the limits specified in GB/T 14549;

b) The interharmonic voltage shall not exceed the limits specified in GB/T 24337;

c) The power grid voltage deviation shall not exceed the limits specified in GB/T

12325;

d) The voltage fluctuation and flicker value shall not exceed the limits specified in GB/T 12326;

e) The three-phase voltage unbalance factor shall not exceed the limits specified in GB/T 15543;

f) The power grid frequency deviation shall not exceed the limits specified in

GB/T 15945.

5.3 Grid-disconnected operation conditions

Grid-connected and grid-disconnected switching type power conversion systems and grid-disconnected type power conversion systems shall operate normally under the following conditions.

a) The rated power of the load shall not be greater than the rated output power of the power conversion system;

b) The load starting current shall not be greater than 1.2 times the rated current of the power conversion system.

6.1 Appearance

The appearance of the power conversion system shall meet the following requirements.

a) The appearance shall be complete, without deformation, peeling, corrosion, cracks or other phenomena;

b) The cabinet doors and switches shall operate flexibly;

c) The nameplate, signs and marks shall be complete and clear;

d) The texts and symbols shall be neat, standardized and correct.

6.2 Protection grade

The protection grade of the enclosure of the power conversion system shall meet the following requirements.

a) The protection grade of indoor type power conversion systems shall be not lower than IP20 specified in GB/T 4208;

b) The protection grade of outdoor type power conversion systems shall be not lower than IP54 specified in GB/T 4208.

7.1 Start-up and shutdown

The power conversion system shall have the start-up and shutdown control function, and be capable of starting up and shutting down the power conversion system according to control switches or commands.

7.2 Power control

The power conversion system shall have active power control and reactive power control functions, and be capable of continuously and smoothly adjusting active power and reactive power as well as switching between charging and discharging according to the control mode or received power control commands. Class A1 and Class A2 power conversion systems should have primary frequency control and inertia response control functions.

7.3 Grid-connected and grid-disconnected switching

The grid-connected and grid-disconnected switching type power conversion system shall have the grid-connected and grid-disconnected switching function, and be capable of switching from grid-connected mode to grid-disconnected mode according to the set conditions, and establishing stable frequency and voltage; and be capable of switching from grid-disconnected mode to grid-connected mode according to upper-level commands, meeting the corresponding power requirements.

7.4 Alarm and protection

7.4.1 The power conversion system shall have a fault diagnosis function, and shall be capable of giving alarms when abnormal conditions occur. The alarm should adopt audible, visual and other indication methods. The alarm contents shall include. reverse polarity connection, incorrect phase sequence of AC incoming line, DC voltage abnormality, overcurrent, overtemperature, communication fault and cooling system fault, etc.

7.4.2 After the power conversion system sends an alarm signal, it shall enter an abnormal operation state or fault protection state.

7.4.3 The power conversion system shall have a fault information recording function, be capable of recording fault and alarm information, and store the information.

7.5 Insulation resistance detection

7.5.1 The power conversion system shall have the DC terminal insulation resistance detection function, and this function may be enabled or disabled as required.

7.5.2 When the insulation resistance value detected by the power conversion system is lower than the set protection value, the power conversion system shall give an alarm and stop operation.

Note. The protection value may be selected by default as the ratio of the maximum

DC voltage to 30 mA.

7.6 Communication

7.6.1 The power conversion system shall have the function of information interaction with equipment such as battery management systems and monitoring systems.

7.6.2 The communication interfaces between the power conversion system and the

battery management system may adopt controller area network (CAN), RS-485,

Ethernet, wireless and other communication interfaces, and support communication protocols such as CAN2.0B, Modbus, DL/T 860 (all parts), and Message Queuing

Telemetry Transport (MQTT).

7.6.3 The communication interface between the power conversion system and the

monitoring system may adopt Ethernet communication interface, and support communication protocols such as Modbus TCP and DL/T 860 (all parts). Dual-network redundant communication should be adopted.

7.7 Operation information monitoring

7.7.1 The power conversion system shall be capable of monitoring in real time the voltage, current, power and battery status information of the DC terminal, as well as the voltage, current, frequency and power information of the AC terminal.

7.7.2 The power conversion system shall be capable of monitoring in real time the communication status between the power conversion system and equipment such as battery management systems and monitoring systems.

7.8 Statistics

7.8.1 The power conversion system shall have a fault information statistics function to realize the query of fault information.

7.8.2 The power conversion system should have charging energy and discharging energy statistics functions to realize the query of charging and discharging energy information.

7.9 Data display and storage

7.9.1 The power conversion system shall have a data display function and be capable of displaying information such as operating status, operating parameters, protection parameters and event records.

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