Centralized Frequency Control of Offshore Hybrid Power Plant
02 HYB24-11
Presented by: Aivaras Celna
Introduction
A Hybrid Power Plant (HPP) is a combination of several renewable energy sources (RES) such as wind and solar combined with energy storage systems (ESS) and/or Power-to-X (P2X) connected behind a single point of connection (POC). The development of such HPPs provides additional flexibility for the plant operation and thus to take advantage of additional revenue streams through new energy markets (hydrogen) and ancillary service markets. However, further expansion of RES creates challenges for the balancing of the electrical power system, as the variable power generation and consumption are increasing while dispatchable power generation is declining at the same time. As a result, transmission system operators (TSO) are forced to activate more power reserves to prepare for more frequent and severe occurrences of imbalances in the future power system.
Frequency Support from HPPs
For frequency regulation, the Danish TSO has established several services: fast frequency reserve (FFR), frequency containment reserve (FCR) for disturbances (-D) and normal operation (-N) as well as frequency restoration reserve (FRR). Large-generation technologies can apply and qualify for the provision of those services in the ancillary service market. However, individual RES have limited capabilities to participate in the aforementioned market, mostly due to their technical limitations and therefore only FCR service has normally been considered in the literature and industry. In HPPs, a combination of technologies expands frequency support possibilities and creates opportunities for enhanced participation in ancillary service markets (including FFR and FRR services) as the qualification is based on the combined response of sub-plant technologies, rather than individual sub-plants. For this purpose, centralized coordinated control and prioritization of HPP assets are required, ensuring precise allocation of multi-timescale power reserves and the compliant combined response of the plant, while taking into consideration variable delays across technologies and control layers as well as differences in technical capabilities of each technology.
The contribution of the paper
This work aims to present the capabilities of large-scale HPPs to provide ancillary services, namely FFR, FCR-D, FCR-N and FRR by coordinating responses from the sub-plant technologies such as Offshore wind, Onshore PV, BESS and P2X electrolyser. The research paper will first give an overview of the Danish grid code technical requirements for the aforementioned frequency services. Further, the control algorithm and allocation of the multi-timescale reserves to each of the technologies will be described in various operating scenarios of HPP. Finally, the discussion on the results of several simulated use cases using RMS model with varying operating conditions (changes in wind and solar resources) and prioritization will be presented, followed by recommendations for further frequency controller development.
A Hybrid Power Plant (HPP) is a combination of several renewable energy sources (RES) such as wind and solar combined with energy storage systems (ESS) and/or Power-to-X (P2X) connected behind a single point of connection (POC). The development of such HPPs provides additional flexibility for the plant operation and thus to take advantage of additional revenue streams through new energy markets (hydrogen) and ancillary service markets. However, further expansion of RES creates challenges for the balancing of the electrical power system, as the variable power generation and consumption are increasing while dispatchable power generation is declining at the same time. As a result, transmission system operators (TSO) are forced to activate more power reserves to prepare for more frequent and severe occurrences of imbalances in the future power system.
Frequency Support from HPPs
For frequency regulation, the Danish TSO has established several services: fast frequency reserve (FFR), frequency containment reserve (FCR) for disturbances (-D) and normal operation (-N) as well as frequency restoration reserve (FRR). Large-generation technologies can apply and qualify for the provision of those services in the ancillary service market. However, individual RES have limited capabilities to participate in the aforementioned market, mostly due to their technical limitations and therefore only FCR service has normally been considered in the literature and industry. In HPPs, a combination of technologies expands frequency support possibilities and creates opportunities for enhanced participation in ancillary service markets (including FFR and FRR services) as the qualification is based on the combined response of sub-plant technologies, rather than individual sub-plants. For this purpose, centralized coordinated control and prioritization of HPP assets are required, ensuring precise allocation of multi-timescale power reserves and the compliant combined response of the plant, while taking into consideration variable delays across technologies and control layers as well as differences in technical capabilities of each technology.
The contribution of the paper
This work aims to present the capabilities of large-scale HPPs to provide ancillary services, namely FFR, FCR-D, FCR-N and FRR by coordinating responses from the sub-plant technologies such as Offshore wind, Onshore PV, BESS and P2X electrolyser. The research paper will first give an overview of the Danish grid code technical requirements for the aforementioned frequency services. Further, the control algorithm and allocation of the multi-timescale reserves to each of the technologies will be described in various operating scenarios of HPP. Finally, the discussion on the results of several simulated use cases using RMS model with varying operating conditions (changes in wind and solar resources) and prioritization will be presented, followed by recommendations for further frequency controller development.