A coordinated control of offshore wind power and bess to provide power system flexibility

Article number 4650The massive integration of variable renewable energy (VRE) in modern power systems is imposing several challenges; one of them is the increased need for balancing services. Coping with the high variability of the future generation mix with incredible high shares of VER, the power system requires developing and enabling sources of flexibility. This paper proposes and demonstrates a single layer control system for coordinating the steady‐state operation of battery energy storage system (BESS) and wind power plants via multi‐terminal high voltage direct current (HVDC). The proposed coordinated controller is a single layer controller on the top of the power converter‐based technologies. Specifically, the coordinated controller uses the capabilities of the distributed battery energy storage systems (BESS) to store electricity when a logic function is fulfilled. The proposed approach has been implemented considering a control logic based on the power flow in the DC undersea cables and coordinated to charging distributed‐BESS assets. The implemented coordinated controller has been tested using numerical simulations in a modified version of the classical IEEE 14‐bus test system, including tree‐HVDC converter stations. A 24‐h (1‐min resolution) quasi-dynamic simulation was used to demonstrate the suitability of the proposed coordinated control. The controller demonstrated the capacity of fulfilling the defined control logic. Finally, the instan-taneous flexibility power was calculated, demonstrating the suitability of the proposed coordinated controller to provide flexibility and decreased requirements for balancing power

The Coordination and control of smart inverters utilizing Volt-VAr and Volt-Watt in low voltage networks, and opportunities for South Africa

Thesis (MEng)--Stellenbosch University, 2022.ENGLISH ABSTRACT: Increasing photovoltaic (PV) penetration in the low-voltage (LV) distribution network leads to grid-interconnection issues for electric utilities. These issues include voltage violations, equipment overloading and frequency instability. To mitigate these problems, advanced smart inverter functionality is becoming increasingly popular in states and countries with high renewable energy penetration levels. Although smart inverters have a wide range of benefits for the utility, these benefits are limited to the local level due to autonomous inverter control. This research investigates the benefits of coordinated inverter control in mitigating voltage violations in LV feeders due to increasing PV penetrations. A critical literature review on the grid interconnection requirements and smart inverter functionality guidelines informs on the gaps that need to be addressed to allow for increased smart inverter deployment in South Africa. The literature review also explores the benefits of distributed energy resource management systems (DERMS) and virtual power plants (VPPs), and the requirements for each platform. Based on the literature review’s findings, a simulation has been conducted to investigate the benefits of coordinated smart inverter voltage regulation control, particularly Volt-VAr and Volt-Watt, to increase hosting capacity in LV networks. The proposed methodology considers the feeder-wide voltage conditions instead of local point of connection (PoC) conditions using sensor measurements, and the fairness of voltage regulation and active power curtailment among customers on a feeder. This proposed methodology can be used as an intermediate solution for coordinating smart inverters without the use of extensive communication infrastructure and advanced aggregating platforms. The simulation results show an improvement in voltage profiles using coordinated Volt-VAr and Volt Watt inverter control and feeder-wide awareness. The improved voltage profiles can accommodate higher levels of PV penetration and thus increase hosting capacities in LV feeders.AFRIKAANSE OPSOMMING: Toenemende fotovoltaïese (PV) penetrasie in die laagspanning (LV) verspreidings netwerk lei tot probleme vir die elektrisiteitverskaffer. Hierdie kwessies sluit spanning skendings, oorlading van toerusting en onstabiliteit in frekwensie in.Gevorderde slim-omsetter funksionaliteit word gebruik om hierdie probleme te verlig en raak dus al hoe meer gewild in state en lande met ʼn hoë opname van hernubare energie. Alhoewel slim omsetters 'n wye verskeidenheid voordele vir die kragstelsel inhou, is hierdie voordele beperk tot die plaaslike vlak as gevolg van outonome omsetter-beheer. Hierdie navorsing ondersoek die voordele van gekoördineerde omsetterbeheer om spanningskendings in LV-netwerke te minimeer. 'n Kritiese literatuuroorsig in netwerkverbindingsvereistes en riglyne vir slim-omsetter funksionaliteit lig uit die leemtes wat opgelos moet word om 'n groter implementering van slimomsetters in Suid Afrika moontlik te maak. Die literatuuroorsig ondersoek ook die voordele van verspreide energiehulpbronbestuurstelsels en virtuele kragstasies, en die vereistes vir elke platform. Op grond van die bevindinge van die literatuurstudie is 'n simulasie uitgevoer om die voordele van gekoördineerde slim-omsetter spanningsreguleringsbeheer, veral Volt-VAr en Volt-Watt, in LV-netwerke te ondersoek om gasheervermoë te verhoog. Die voorgestelde metodologie neem in ag die toevoer-wye spanningstoestande, die billikheid van spanning regulering, en die aktiewe kragbeperking onder kliënte. Hierdie voorgestelde metodologie kan gebruik word as 'n intermediêre oplossing vir die koördinering van slim-omsetters sonder die gebruik van uitgebreide kommunikasie-infrastruktuur en gevorderde samevoegings platforms. Die simulasie resultate van om die gekoördineerde Volt-Watt-omsetterbeheer en netwerk-wye bewustheid te gebruik, toon 'n verbetering in spanningsprofiele. Die verbeterde spanningsprofiele kan hoër vlakke van PV-opname akkommodeer en dus gasheer kapasiteit in LVnetwerke vergroot.Master