ERA Responsibility: Executing Entity

Client: CPFL Energia

ANEEL R&D ID: PD-00063-3085/2022

Duration: 30 months

Other Executing Entities: University of Campinas – UNICAMP; São Carlos School of Engineering – University of São Paulo (EESC–USP); The Western Paraná State University – UNIOESTE

Project Segment: Power distribution systems

Research Theme: OP06 - Study, simulation, and performance analysis of electrical power systems

Phase in the Innovation Chain: AR – Applied Research

Abstract: The increase of distributed generation (DG) levels in power distribution systems has concerned the National Power System Operator (ONS) due to the potential negative impacts on the stability of the Interconnected National System (SIN). As a result, the ONS has suggested to the Brazilian Electricity Regulatory Agency (ANEEL) to adopt minimal requirements for anti-islanding protection and regulation curves of distributed generation. For anti-islanding protection, the main concern is the massive tripping of distributed generation during disturbances in the SIN, aggravating the effects of these disturbances. Similarly, the adoption of minimal requirements of DG regulation can provide further support to the frequency and voltage regulation in the SIN. On the other hand, the adoption of these requirements may create other issues that must be studied in power distribution systems. Among them, if an island occurs, the protection of DGs must rapidly disconnect them, guaranteeing the crew and customers safety and avoiding equipment damage. Therefore, the modification of the protection requirements may impact key functions of the anti-islanding protection. For the regulation curves, this conflict affects the DG owners, as they may have their operational costs increased. In this context, this project proposes to develop risk-based, cost-benefit, and techno-economic methodologies to solve potential conflicts considering the perspective of distribution power systems, DG owners, and regulatory agencies. The goal is that these methodologies must have an easy implementation, consider different technologies, passive and active anti-islanding protection schemes, and different DG penetration levels in low, medium, and high voltage distribution systems. For passive anti-islanding protection, the functions of under/overfrequency, under/overvoltage, rate of change of frequency, and rapid rate of change of frequency will be analyzed. For active protection, this project will study the ones based on voltage and/or frequency positive feedback. In summary, the proposed methodologies will provide technical and economic support (i.e., cost analysis of all solutions) to solve the conflict in a cost-effective manner for the ONS, distribution utilities, and DG owners. Thus, the methodologies will allow utilities to evaluate the risks of protection and regulation violations in terms of the penetration and operational DG characteristics.

Keywords: Distributed generation, islanding detection, protection, regulation curves, risk-based methodology.

ERA Responsibility: Executing Entity

Client: CPFL Energia

ANEEL R&D ID: PD-00063-3091/2023

Duration: 48 months

Other Executing Entities: University of Campinas – UNICAMP

Project Segment: Power distribution systems

Research Theme: OP06 - Study, simulation, and performance analysis of electrical power systems

Phase in the Innovation Chain: AR – Applied Research

Abstract: The primary objective of this project is to develop methodologies for efficient calculation of hosting capacity (HC) of distributed generators (DGs) on low and medium voltage systems, and methodologies to determine the most suitable reinforcements in different regions and scenarios of DG integration. These methodologies will be implemented as modules of a computational tool in four stages: two stages dedicated to the development of stochastic and analytical methods for HC calculations and low voltage reinforcements, and two stages dedicated to the development of deterministic and analytical methods for HC calculations and medium voltage reinforcements. The distinctive aspect of these methodologies lies in their comprehensive coverage, allowing them to handle connection requests with diverse characteristics (such as single, two and three-phase, with different power levels and connection points) across multiple voltage levels. Furthermore, these methodologies have the capability to identify the most appropriate reinforcements for a wide range of scenarios. The automatization of connection requests can bring significant benefits to the utility such as the reduction of the time and effort expended on analyses, while the automated management of reinforcements can reduce costs associated with voltage violations and technical losses. The methodologies and the computational tool are applicable to the engineering asset management departments, which traditionally rely on low-level automation processes for handling connection requests. Specifically, the methodologies can aid the engineering department in the management of connection requests on medium voltage, while the asset management department can utilize them for low voltage requests. The relevance of this project encompasses all utilities and end customers. By streamlining the evaluation process for connection requests, the project has the potential to reduce utility costs, both in terms of man-hours and reinforcements. Additionally, it can prevent power quality issues. Enhanced efficiency and reinforcements contribute to a lower energy cost, directly benefiting the end customers. Finally, the outcomes of this project can also subsidize updates in the current regulation about connection requests of DGs.

Keywords: Distributed generation, distribution systems, hosting capacity, reinforcement.

ERA Responsibility: Supporting Company

Client: Universidade de São Paulo (USP)

ANP R&D ID: 23658-8

Duration: 36 months

Project Area: Other Energy Sources / Other Alternative Sources / Hybrid Systems

Phase in the Innovation Chain: AR – Applied Research

Object of Contract: Computer Implementation of Electric Models

Abstract: Modern electrical energy distribution systems are experiencing significant changes, especially with the rapidly increasing penetration of distributed energy resources (DERs), such as photovoltaic and wind generators, electrical vehicles, and energy storage systems. These devices use power electronic-based technologies, which may present negative resistance characteristics at specific frequencies. Therefore, these power electronic-based DERs have the potential to decrease resonance damping in the electrical system and, consequently, damage circuit equipment and customer loads (customer processes). This can create significant financial losses not only to the distribution utility, but also to the end customer. As the high penetration of DERs in distribution systems is a relatively recent trend, it remains unclear which are the main characteristics and most critical scenarios of these resonances. In addition, there are no well-established methods to anticipate the risk of these problematic resonances and mitigate them. In this context, the goal of this project is to provide a detailed characterization of these resonances in DER-rich distribution systems and develop methods to predict the risk of occurrence of these problematic resonances and mitigate this risk, avoiding costly damages to circuit equipment. The main focus is on the development of systematic methods that can speed-up the decision-making process of engineers in terms of which actions should be undertaken to avoid or eliminate resonances, either during planning or operation of DER-rich distribution systems. The results of this project will be used not only to reduce the risks and costs associated with technical losses and device damages, unplanned disconnection of customer processes, equipment lifetime reduction, and number of man-hours needed to manage these resonances. The results of this project can also be used to support the improvement of national regulations for DER integration into the distribution systems.

Keywords: Distributed energy resources, distribution systems, resonance.

ERA Responsibility: Supporting Company

Client: Universidade de São Paulo (USP)

ANP R&D ID: 23673-7

Duration: 36 months

Project Area: Other Energy Sources / Other Alternative Sources / Wind Energy

Phase in the Innovation Chain: AR – Applied Research

Object of Contract: Computer Implementation of Electric Models

Abstract: Modern electrical energy distribution systems are experiencing significant changes, especially with the rapidly increasing penetration of distributed energy resources (DERs), such as photovoltaic and wind generators, electrical vehicles, and energy storage systems. These devices use power electronic-based technologies, which may present negative resistance characteristics at specific frequencies. Therefore, these power electronic-based DERs have the potential to decrease resonance damping in the electrical system and, consequently, damage circuit equipment and customer loads (customer processes). This can create significant financial losses not only to the distribution utility, but also to the end customer. As the high penetration of DERs in distribution systems is a relatively recent trend, it remains unclear which are the main characteristics and most critical scenarios of these resonances. In addition, there are no well-established methods to anticipate the risk of these problematic resonances and mitigate them. In this context, the goal of this project is to provide a detailed characterization of these resonances in DER-rich distribution systems and develop methods to predict the risk of occurrence of these problematic resonances and mitigate this risk, avoiding costly damages to circuit equipment. The main focus is on the development of systematic methods that can speed-up the decision-making process of engineers in terms of which actions should be undertaken to avoid or eliminate resonances, either during planning or operation of DER-rich distribution systems. The results of this project will be used not only to reduce the risks and costs associated with technical losses and device damages, unplanned disconnection of customer processes, equipment lifetime reduction, and number of man-hours needed to manage these resonances. The results of this project can also be used to support the improvement of national regulations for DER integration into the distribution systems.

Keywords: Resonance, transmission systems, wind energy.

ERA Responsibility: Contractor

Client: Electric Power Research Institute (EPRI)

EPRI Agreement No.: 10017497

Duration: 9 months

Project Area: Power distribution systems simulation

Object of Contract: Software development

Abstract: EPRI’s OpenDSS is the Open-source Distribution System Simulator released to the public in 2008 under proprietary licensing. Since then, multiple parties between electric power utilities and academic users worldwide have been using it for validating simulations, creating their own derivative applications, and advancing analysis for the electric power industry. This software has been a vital non-commercial tool used by EPRI as a vehicle for demonstrating research concepts across the industry. Originally developed in Delphi, OpenDSS has kept growing since its conception to incorporate specialized analysis as well as compatibility with modern computing technologies. In 2021, EPRI started a project to translate the source code of OpenDSS from Delphi to C++, supporting cross-platform integration. The C++ version of OpenDSS (also Called OpenDSS-C) offers an opportunity to keep learning about the tool usage and feasible advancements, leading this project into a new stage of development looking for adopting improvements proposed by external developers to the platform. In partnership with the UNICAMP’s research group led by Prof. Walmir Freitas, ERA is selected to evaluate, validate, and implement new features and improvements on the OpenDSS-C.

Keywords: C++, Distribution systems simulation, OpenDSS.