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The electric power system is rapidly transforming to address the urgent need for decarbonization and combat climate change. Integration of renewable energy sources into the power grid is accelerating, creating new challenges such as intermittency and uncertainty. To address these challenges, this paper proposes a new design of automatic generation control (AGC) ancillary service cost allocation based on the causer-pays rule. The proposed design treats reserves as inventory and aims to minimize them by allocating costs among consumers based on the causative factors for AGC operation. Two cost-allocation methods based on the causer-pays principle are introduced. The first method distributes costs according to the changes in loads causing ancillary service operation, while the second method considers opportunity costs. The case study on the IEEE 39 Bus System demonstrates that the proposed methods incentivize consumers to minimize volatility, resulting in reduced reserve requirements for system operation. In particular, the opportunity cost-based approach encourages loads and variable renewable energy (VRE) to actively reduce volatility, resulting in more efficient power system operation. In conclusion, the novel AGC ancillary service cost allocation methods offer a promising strategy for minimizing spinning reserves, increasing the power system's efficiency, and incentivizing consumers to actively participate in frequency regulation for a more sustainable and reliable electricity market. [ABSTRACT FROM AUTHOR]

Considering the controllability and high responsiveness of an energy storage system (ESS) to changes in frequency, the inertial response (IR) and primary frequency response (PFR) enable its application in frequency regulation (FR) when system contingency occurs. This paper presents a coordinated control of an ESS with a generator for analyzing and stabilizing a power plant by controlling the grid frequency deviation, ESS output power response, equipment active power, and state of charge (SoC) limitation of the ESS in a power plant. The conventional generator and FR-ESS controllers were investigated and compared. To obtain the optimal frequency and power response, an ESS-based adaptive droop control method was proposed. The proposed control strategy was developed and implemented considering the changes and limitations of the dynamic characteristics of the system, FR requirements, and an ESS using the PSCAD/EMTDC software. The simulation results showed that the proposed method was more effective than the conventional droop-control-based FR-ESS, and the effectiveness of this method was validated. [ABSTRACT FROM AUTHOR]

Advanced controllers have been widely introduced in power system-related research to alleviate the uncertainties of renewable sources. The performance of the controllers should be verified in a realistic environment before the controllers are used in practical applications. This study focuses on voltage regulation of wind farms in voltage drop cases where communication failures occur and discusses modifications done on the online wind farm management system. The modified management system is designed to respond to a voltage drop when the outer reference signal from the upper-level controller is absent due to technical problems, especially communication errors. Such a situation has not been considered in most of the management systems in the literature. The predictable situations in real fields have been further verified under the hardware-in-the-loop simulation environment RTDSTM. During communication failure, the proposed method can respond automatically to voltage recovery, along with a designed objective function. A comparative analysis of actual control modes was also conducted to prove the relevance and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

As demand for electric vehicles (EV) grows, interest in vehicle‐to‐grid (V2G) is increasing. Although V2G provides additional flexibility for power systems, it can be an inconvenience for the EV owner and shorten the cycle life of EV batteries. In this paper, we propose a power‐imbalance‐based droop control (PIDC) for V2G, which uses estimated active power imbalance between supply and demand, without any communications or dispatch signal from the automatic generation control (AGC). Unlike the existing frequency droop control, the proposed method controls V2G based on the estimated imbalance. The Imbalance between electricity supply and demand was estimated using the swing equation, frequency deviation, and rate of change of frequency (RoCoF). Conventional frequency droop control has a slow response speed because it only considers the frequency deviation. Using the PIDC, the critical frequency drop was discerned faster and the V2G could react more quickly in critical frequency drop situations. Additionally, battery cycle life was preserved in ordinary frequency fluctuations where V2G is unnecessary. This study used MATLAB R2020a to show the effectiveness and performance of PIDC. The case study results showed that PIDC has a faster response speed and preserves EV battery cycle life compared to frequency droop control. [ABSTRACT FROM AUTHOR]

This study considers the optimal reactive power dispatch strategy that minimizes electrical loss while working within the constraints of the internal layout voltage. Wind turbines (WTs) with a power converter system can promptly generate reactive power, and when a reactive power order arrives from the connected grid, an operator can assign a reactive power reference to each wind turbine. Recently, multiple objective functions in use have been based on centralized control, but their flexibility has been determined as inadequate for situations in which the voltage range of the wind turbine is also a factor. The designated constraints of the voltage fluctuation for each section have thus been considered by designing and applying an adaptive method. The main purpose of such a method is to use general dispatch optimization while maintaining the voltage of each connection point within operating range. The included case studies are designed using an electromagnetic transients program that checks both the voltage and loss of the entire wind farm. We tried to identify voltage violations and confirmed the effectiveness of the proposed method. This work thus attempts to confirm whether an objective function can be implemented while also adhering to a certain grid code. [ABSTRACT FROM AUTHOR]

The Korean government is targeting the development of a renewable energy penetration of 30–35% by 2040 of the total generation. These conditions will decrease network stability due to a lack of inertia, especially in isolated systems, such as Jeju Island. HVDC systems with several balancing arrangements of reserve operation are used to maintain variability and uncontrollability of RES penetration. This paper presents the fast frequency reserves of HVDC control systems for frequency stability enhancement in the isolated power system by using a combined frequency containment process with grid stability standards. A new MIDC reserve operation control with angle and voltage deviation at the bus converter was developed to provide a faster and more appropriate balancing arrangement compared to the other concept. In addition, two layers of energy and transfer-capacity flexibility were considered to prevent the need to hunt for that balancing arrangement, as well as low nadir frequency, unavailability of the reserve and other constraints caused by each region having a different network size, HVDC interconnection capacity, and type. The proposed control schemes were verified by simulations on the Korean power system model implemented in PSS/E for different sizes of disturbance. [ABSTRACT FROM AUTHOR]

Frequency droop control is a simple and effective frequency control method. However, it is not appropriate as a primary frequency control for microgrids with energy storage systems and voltage source converters (VSCs) owing to their slow response speed. In addition, it is difficult to determine the grid balance only with frequency deviation. In this paper, a new converter‐fed microgrid primary frequency control method based on the estimated active power imbalance for fast response and less variability in the transmission system is proposed. The active power imbalance is estimated via frequency deviation, frequency drop speed and the modified swing equation. The estimated imbalance indicates the status of the power imbalance more quickly and accurately than the frequency deviation. The proposed method does not require communication devices, responds quickly to frequency drops, and prevents unnecessary operation of the grid‐connected VSC because it uses the estimated imbalance instead of the frequency or angle for droop control. Simulation results show that the proposed method is significantly faster than frequency droop control methods, improves the rate of change of frequency and frequency nadir and reduces variability in the transmission system. [ABSTRACT FROM AUTHOR]

With the increasing number of embedded high‐voltage DC (HVDC) projects in AC systems, there is growing research interest in controlling the operating point of the HVDC in real time. This real‐time operation system requires the AC system information to be continuously updated, which involves practical challenges such as the burden of communication. To mitigate this problem, this paper proposes a novel technique to screen the AC system monitoring area for the efficient operation of the embedded HVDC. The screening algorithm determines the monitoring area by HVDC sensitivity analysis using the power transfer distribution factor. Then, a reliable and efficient grid operation is enabled using the limited data obtained from the determined area. The proposed methodology is verified using a Korean power system with multiple HVDCs. The effectiveness and advantages of the proposed technology are verified by comparing the results obtained using the system‐wide data with those obtained from the monitoring area. [ABSTRACT FROM AUTHOR]

Growth of renewable penetration will increase the requirement for flexible resources. It may be a simple solution to build more flexible resources, but it is too expensive. Recently, the new construction of power plant or transmission line has faced opposition by the resistance of the local residents. Depending on the needs, new methodologies are required in order to gain the flexibility of the power grids. This paper proposes the flexible frequency operation strategy with significant renewable penetration to achieve the flexibility of the power grids. Flexible frequency operation provides customized frequency through BTB HVDC, and the overall system is operated with relaxed frequency regulation. By reducing the need and role of the frequency ancillary service reserve, an operator does not need to secure additional governor response reserve for renewable energy. In order to model frequency dynamic of high renewable penetrated power system, the swing equation is modified in this paper. The case studies using MATLAB show effectiveness of flexible frequency operation strategy. [ABSTRACT FROM PUBLISHER]

In the aspect of power grid, attention is being given to conditions of environmental variation along with the need for precise prediction strategies based on control elements in recently designed large-scale distributed generation systems. With respect to distributed generators, an operational prediction system is used to respond to the negative impacts that could be generated. As an active response plan, efforts are being made by system operators to cover fluctuations with utilization of battery-based storage devices. Solar or ocean energy that shares electrical structure with an energy storage system has recently being seen as a combined solution. Although this structure is supported by a state analysis plan, such methods must be performed within the range where the response is possible under consideration of the power requirements of the electronic devices. This paper focuses on an iterative based solution for enhancing response of storage that included in DC generation system, to check its availability in terms of possible calculation load. A previous storage management plan was utilized and tested using a commercially available transient electromagnetic simulation tool that focused on possible delays. Case studies were performed sequentially on the time delays based on utilizable inverter topologies. [ABSTRACT FROM AUTHOR]