1. Storage Connection requirements
General Overview and implementation approach
Belgian Working Group
1st December 2017
Aymen Chaouachi

2. Scope and implementation
Overview
General Provisions 1
Scope and implementation 2
Storage requirements Track Change 3

3. General Provisions 1
Notions de base sur le marché de l’électricité

4. Why a dedicated Storage Connection Requirement?
RfG
DCC
HVDC
Network codes
Connection
requirements
Network Code compliance
E&R Network Code
SO Guidelines
Storage inherent characteristics
Fast ramping capabilities
Cold-Load pickup during reconnection
Storage Operation Modes
Charging and discharging modes
Active power control
Except for pumped storage, Explicitly out of scope
Electricity scenarios for BE 2050
Needs for Storage Requirements
Drivers for dedicated Storage Requirements

5. Electric Energy Storage Types
Mechanical
Pumped Hydro*
Compressed Air
Flywheels
Electrical
Capacitors
Magnetic coils
Chemical
Batteries
Fuel cells
Connected via SM
Connected via Converters**
* Covered in RfG
** Similar technical capabilities to PPM

6. General points of consideration
Typically a storage system is a Controllable power injector or load behind a converter with similar characteristics to a PPM: The converter in this case can act as an inverter (discharging mode) or rectifier (charging mode)
Constraints wise:
No minimum regulating power Pmin (+) Very Fast ramping capabilities (+-)
Minimum or maximum state of charge (-)
Implementation of requirements within a dedicated section:
Similar granularity as per the RfG SGUs
Dedicated requirements in alignment with the RfG PPM capabilities
Adaptations to take into consideration specific nature of storage and other NCs provisions (SO GL and E&R NCs)

7. Scope and implementation2
Notions de base sur le marché de l’électricité

8. Storage System requirements: Scope
Public Transmission network
Gen = ~
POCC
SPM
Central Control
Storage Park Module (SPM): An electric system composed of a single or multiple electrical storage units capable of storing, delivering electrical energy into a single electrical point of connection.
Possible Operational modes
Charging Source
Discharging sink
Case 1
Public Network
Case2
Local facility (local demand)
Case 3
Local facility (local generation)
Case 4
Not applicable to emergency generation operating in parallel less than five minutes per calendar month while the system is in normal system state;
Cover both permanently or temporarily connected batteries as Vehicle2Grid applications.

9. New set of definitions – To be used and defined in the FGC
General
Storage Park Module (SPM) An electric system composed of a single or multiple electrical storage units capable of storing, delivering electrical energy into a single electrical point of connection.
Characteristics
Pcmax: Allowable maximum charging at the point of common coupling.
Pdmax: Allowable maximum discharging at the point of common coupling.
Prated: The highest active power which the SPM is designed to deliver or absorb at the point of common coupling (used to determine the SPM Type).
State Of Charge (SOC): Is the measure of the amount of capacity remaining expressed in percentage points (0% = empty; 100% = full).
Minimum/Maximum State of Charge: Are the limitation in term of storage capabilities
Operation
Charging Mode / Discharging Mode
Nominal charging and discharging rates
Fast charging and discharging rates (e.g. EV charging stations)

10. Requirements mapping Very Common Common >0.25 MW Rare >25 MW
Alignment with C10/11
Type A PGM
Type A SPM
Very Common
Type B PPM
Type B SPM
Common
>0.25 MW
Type C PPM
Type C SPM
Rare
>25 MW
Type D PPM
Type D SPM
Very rare
>75 MW
Voltage Connection level is not considered in the determination of the Storage Type
Requirements Type shifting

11. Storage requirements Track Change2
Notions de base sur le marché de l’électricité

12. Approach for trach-changes
Similar characteristics to a PPM: full new set of technical requirements coming from the NC and not yet in the FGC
Not an isolated chapter in the FGC => not the approach of having a “full grid code for storage”
Use of references to technical requirements to PPM or PGM, when appropriate : to limit double writing of the same rule
To refer indirectly to the NC RfG, when the PPM or PGM articles are referring to the RfG
Specific Sub-Section devoted for storage, to add readability in the FGC
Limited to technical requirements

13. Type A: Track Change RfG Reference Requirement Adaptation [Art. 13-4]
Admissible maximum power reduction with falling frequency
Not applicable
[Art. 13 (2)(b)]
Use of automatic disconnection and reconnection (LFSMO)
[Art. 13 (2)]
Limited frequency sensitive mode – Overfrequency
Yes
[Art 13-6]
Logical interface to cease active power injection
[Art 13.7]
Conditions for automatic connection to the network
[Art. 15(2)(c)]
Limited frequency sensitive mode – Underfrequency
Yes*
[Art 15.6(e)]
Ramping Limits
* Applicable to all Type A, B, C and D

14. Type B: Track Change RfG Reference Requirement Adaptation Vs RfG
[Art (a)]:
Reduce active power output
Yes
[Art 14-4]
Conditions for automatic re-connection to the network
[Art 20-2(a)]
Reactive Power Capabilities
[Article 20 (2) b/c]
Fast fault current injection
Yes*
[Article 20(3)]
Priority to active or reactive power contribution
* Optional requirement

15. Type C: Track Change RfG Reference Requirement Adaptation Vs RfG
[Art 15.2.(a)]
Time period for frequency stability to be reached
Yes
[Art 21 (3)(a-c)]
Reactive power capabilities
[Art 15 (2) (d)]
FSM requirements
Reference to the general framework
[Art 15.2.(e)]
Specifications of the Frequency Restoration Control