Grid Assets Research Articles

Control Center Designs: New Functions and Challenges for the Transmission System Operator

Transmission System Operators (TSOs) are facing major challenges and becoming key players in the transition of the power industry that is enabling the growth of renewable intermittent energy sources. The energy market no longer guarantees long-term revenue when decisions result in building more grid assets. Finally, customer behavioral changes and new energy delivery use requirements appear for the system operator.

Grid Resilience by Power Electronics: Use Subtransmission HVDC Interties for Novel Emergency Power Control of Split Networks [Expert View

Grid resilience by power electronics use subtransmission HVDC interties for novel emergency power control of split networks Modern society is becoming increasingly dependent on reliable electric grids. For years, many critical functions have used backup systems to maintain normal or basic functionality during disturbances. However, it is not possible to back up the entire grid, much less all individual grid assets. In recent years, several devastating natural disasters have struck with great force, causing blackouts on a large scale and putting people and civil functions at risk. Therefore, new methods of improving grid resilience, limiting the spread of blackouts, and providing provisions for the rapid recovery of power grids are needed.

Research on Key Risk Source Identification of Asset Management in Power Grid Enterprise

Asset management uses a process analysis and identification method for various risk sources to identify a series of flowcharts in the form of several sub-modules in accordance with the steps or stages of grid asset management, demonstrate events or states that cause the risk to be generated by identifying various potential risk factors or risk events at each stage. Combined with the goal-oriented identification method to analyze and diagnose the risk indicator, list the detailed risk list, accurately record and manage the common risks existing in the enterprise, and use the reverse push down method, when the asset-related risks are identified, at the same time, record it in a manner that is appropriate to the type of asset or asset system.

安全标签在电网资产管理中的应用

安全标签在电网资产管理中的应用

Energy Management and Optimization Methods for Grid Energy Storage Systems

Today, the stability of the electric power grid is maintained through real time balancing of generation and demand. Grid scale energy storage systems are increasingly being deployed to provide grid operators the flexibility needed to maintain this balance. Energy storage also imparts resiliency and robustness to the grid infrastructure. Over the last few years, there has been a significant increase in the deployment of large scale energy storage systems. This growth has been driven by improvements in the cost and performance of energy storage technologies and the need to accommodate distributed generation, as well as incentives and government mandates. Energy management systems (EMSs) and optimization methods are required to effectively and safely utilize energy storage as a flexible grid asset that can provide multiple grid services. The EMS needs to be able to accommodate a variety of use cases and regulatory environments. In this paper, we provide a brief history of grid-scale energy storage, an overview of EMS architectures, and a summary of the leading applications for storage. These serve as a foundation for a discussion of EMS optimization methods and design.

Information access for event-driven smart grid controllers

Abstract Control of assets in electricity distribution grids is becoming an increasingly interesting solution to address challenges arising in the grid with an increasing penetration of distributed renewable energy generation. This paper looks at a voltage control scenario in low voltage (LV) distribution grids, which targets a reduction of over- and under voltage level situations by adjusting reactive power production of selected low voltage grid assets. The paper models different information access schemes between remote assets and controller, which is activated only when certain voltage thresholds have been crossed at any measurement point in the grid. We assess the information access methods on information reliability and how this affects control performance. We focus on two different information quality metrics; (1) information age and (2) mismatch probability, which are expressed via stochastic models. We investigate in this paper the suitability for using these two metrics for optimization in a voltage grid control scenario. We conclude that, while the mismatch probability is very useful compared to the simpler information age metric from a network designers and operators point of view in setting quality of service requirements, it is not as helpful for control engineers.

Research on Key Risk Index System of Asset Management in Power Grid Enterprise

In this paper, a process analysis and identification method is adopted to identify various risk sources in asset management. According to the steps or stages of grid asset management, a set of key process risk factors is formed in the form of several sub-modules. By identifying various potential risk factors or risk events at each stage, we can describe the events or stages caused by risk. Thus we can build a key risk indicator system for power grid enterprise asset management.

Co-Optimization of Distribution Transformer Aging and Energy Arbitrage Using Electric Vehicles

The advent of electric vehicles (EVs) will bring forth increases in power transmitted over longer periods of time through the distribution power grid. Such an effect will result in accelerated loss-of-life of distribution grid assets including pole-top transformers. As preventive and corrective measures, the charging of the set of EVs connected to a particular pole-top transformer can be centrally managed (e.g., by a distribution system operator or independent aggregator). This paper proposes a centralized model to co-optimize the transformer loss-of-life with the benefits for EVs’ owners on charging/discharging management. The proposed model is compared against a decentralized optimization model in which EVs’ owners optimize their benefits, while ignoring the effect on the transformer. Results show the benefit of the centralized strategy in maintaining the grid assets, while modestly reducing consumers’ arbitrage benefits.

Pilot project using curtailment to increase the renewable energy share on the distribution network

Going to a green electricity landscape needs to cover not only the cost of the renewable production units, but also the cost for their full integration in the system. Hence, the additional costs of congestion and balancing need to be considered as well. Solving congestion issues by investing in new grid assets can be a costly and time-consuming way to integrate new renewables to the grid. Hence, the Belgian distribution network operator Eandis started a pilot project on wind turbine control where a traditional connection would not have been possible for the wind turbines. This ‘smart’ connection solves congestion issues and allows more renewable energy on the grid. This seems contradictory, but controllability does not necessarily mean curtailing, as discussed in the paper. It signifies an opportunity for better utilizing the grid assets and allowing more green energy production units in the electric power system. This paper discusses the results of the pilot project.

Double-Layer Zeolite Nano-Blocks and Palladium-Based Nanocomposite Fiber Optic Sensors for Selective Hydrogen Sensing at Room Temperature

Double-layer fiber optic sensors have been fabricated and tested for hydrogen (H 2 ) gas at room temperature. The optical fiber was coated with a palladium/silica (Pd/SiO 2 ) sensing layer and a zeolite nano-blocks filter layer. The sensors demonstrated clear sensitivity to a broad range of H 2 concentrations. The selectivity study was focused on methane (CH 4 ) and carbon monoxide (CO). It was found that CH4 had no influence on the sensing response while the filter layer minimized the CO interference. The double-layer sensors are, thus, potentially useful for online monitoring of dissolved H2 in power transformers and other electrical grid assets which utilize insulation oils.

Evaluation of PV hosting capacities of distribution grids with utilisation of solar roof potential analyses

Increasing distributed photovoltaic (PV) systems can lead to voltage violations and overloading of grid assets in distribution grids. This raises the necessity to consider the future growth of installed PV capacity for the planning process of distribution system operators (DSOs). This study proposes the combination of a solar roof potential analysis and grid integration studies at the medium-voltage (MV) level. Three different methods are developed to assume the distribution of PV along the feeders based on the solar roof potential, and subsequently to estimate the PV hosting capacity of these feeders. The results show that the approach with an even distribution of PV systems along the feeders leads to higher hosting capacity of PV for the analysed grids. In addition, for most analysed feeders in this study, an overloading of MV/LV (low voltage) transformers is expected to be the limitation of hosting capacity for potential PV systems.

Multi-temporal robust expansion planning of distribution grids considering uncertainties and curtailment of RES

This study focuses on the rising complexity of network expansion planning due to different sources of uncertainty and the transformation into a smart grid environment. Both have to be considered in the process of determining the optimal multi-annual expansion plan. Owing to long life-spans and high investment cost of the grid assets, robust investment decisions avoiding sunk-cost are crucial. Thus, a stochastic, multi-step optimisation programme has to be solved. This study presents a new hybrid-heuristic optimisation approach to derive optimal multi-annual investment decisions considering the uncertainty of the renewable energy sources (RES) development and flexibility options on the example of an RES curtailment.

Managing Demand for Plug-in Electric Vehicles in Unbalanced LV Systems With Photovoltaics

Although the future impact of plug-in electric vehicles (PEVs) on distribution grids is disputed, all parties agree that mass operation of PEVs will greatly affect load profiles and grid assets. The large-scale penetration of domestic energy storage, such as with photovoltaics (PVs), into the edges of low-voltage grids is increasing the amount of customer-generated electricity. Distribution grids, which are inherently unbalanced, tend to become even more so with the uneven spread of PVs and PEVs. In combination, PEVs and local generation could provide voltage support for distribution networks, and support increased penetration. This paper develops an interactive energy management system for incorporating PEVs in demand response (DR). Using this system, owners can immediately choose whether they want to discharge their PEV battery back into the grid. The system not only provides owners with a flexible scheme for contributing to DR but also ensures that, through real-time collaboration of PEVs and PVs, the three-phase grid operates within acceptable voltage unbalance. An extensive performance evaluation using MATLAB/GAMS simulation of the 123-bus test system verifies the effectiveness of the proposed approach.

Automatic Fault Tolerant Regular Monitor Software System in Alchemi Grid Middleware

Fault tolerant resource defence is a critical essential for observes in desktop computational grid. The center of attention of this paper to investigate on Fault Tolerant asset taking care of computational force. Alchemi Desktop grid assets require collecting available computational Power. The Alchemi Desktop grid is a important middleware structure to pull together computational strength by an executor for diverse machines. Breakdown and Error in executor machine can create a problem for desktop grid middleware. Execution level flaws are an exceptionally crucial in the Alchemi desktop grid middleware. This issue has not addressed in Alchemi Desktop Middleware. Alchemi Desktop Grid Middleware provides physical procedure for control executor faults. No automatic system exhibit for execution level deficiencies in Alchemi desktop framework middleware. Today we require computerized technique for consistent and adequate machines in Alchemi Desktop middleware. Our Research effort has Designed, Projected and developed mechanized software system based on regular monitor system. Consistent and Defective Machines can distinguish in shared association. Results demonstrate that automatic software system is Cooperative for Monitor and control on executor faults in Alchemi desktop middleware. Agent can start and cease with help of automated system .Proposed automatic system can perform in Milliseconds. Structure is skilled to sense blemished asset and capable to amend the deficiency in execution machine .It will steady to safeguard level of realistic computational force. Keywords: Computational, fault Tolerant, Alchemi, middleware; Desktop grid

Wireless Sensor Network Based Smart Grid Communications: Cyber Attacks, Intrusion Detection System and Topology Control

The existing power grid is going through a massive transformation. Smart grid technology is a radical approach for improvisation in prevailing power grid. Integration of electrical and communication infrastructure is inevitable for the deployment of Smart grid network. Smart grid technology is characterized by full duplex communication, automatic metering infrastructure, renewable energy integration, distribution automation and complete monitoring and control of entire power grid. Wireless sensor networks (WSNs) are small micro electrical mechanical systems that are deployed to collect and communicate the data from surroundings. WSNs can be used for monitoring and control of smart grid assets. Security of wireless sensor based communication network is a major concern for researchers and developers. The limited processing capabilities of wireless sensor networks make them more vulnerable to cyber-attacks. The countermeasures against cyber-attacks must be less complex with an ability to offer confidentiality, data readiness and integrity. The address oriented design and development approach for usual communication network requires a paradigm shift to design data oriented WSN architecture. WSN security is an inevitable part of smart grid cyber security. This paper is expected to serve as a comprehensive assessment and analysis of communication standards, cyber security issues and solutions for WSN based smart grid infrastructure.

Voltage Regulating Distribution Transformers as new Grid Asset

Since 2012 voltage regulation distribution transformers (VRDT), that is distribution transformers equipped with on-load tap-changers, have become a new grid asset in frequent use. While initially started as a means to facilitate the economic integration of renewable energies into public power grids, it has become apparent that there is a multitude of use cases for VRDTs beyond renewables integration and that the technology is not limited to public grids but can also find applications in industrial grids and become part of generation units. The primary driver behind these new found fields of application for distribution transformers with on-load tap-changers is a new generation of such tap-changers which is much more compact and much more economical than traditional tap-changers.

Evaluation of communication network state estimators for adaptive power-balancing

Smart grid applications are going to reach the low voltage grid assets and households in order to efficiently use the resources in electrical distribution grids. A cost effective way to connect these devices is to utilize the existing network infrastructure or Power-Line Communication (PLC). In this work, we illustrate the impact of changing communication properties on a power balancing controller used to support frequency control in the setting of a microgrid. More specifically, we focus on PLC communication and show how time-varying delays can affect the control algorithm performance. Further, we propose and compare two different delay estimation techniques and demonstrate how the control algorithm can use this information to adapt its gains - yielding significantly better control performance, compared to the controller using static gains.

Modeling study on flexible load's demand response potentials for providing ancillary services at the substation level

Demand response (DR) is an important component for the establishment of smart electricity grids. It can decrease the system peaks through load shedding or shifting and optimize the utilization of the existing grid assets, which delays the need for costly upgrades. DR can also enable the integration of intermittent and distributed energy resources (DER) into the existing electricity grid. Fast DR from aggregated flexible loads can provide ancillary services (AS) to absorb grid disruptions and may replace the expensive fast-ramping reserve generation units. This study presents a methodology for load aggregation based on the prioritization of loads according to their flexibility. Different flexible load types are categorized as thermostatically controlled loads (TCL), urgent non-TCL, non-urgent non-TCL, and battery-based loads. Models based on their physical behaviour are developed and simulations performed to apply the proposed aggregation and control algorithm. Results show that the loads during peak hours can be shed off without rebound demand spikes after the DR event commonly seen in other types of DR programs. The algorithm also automatically adjusts the power demand according to the output of the distributed renewable generation, mitigating disruptions due to variations of the DER output. Additionally, the algorithm is able to adjust the load demand dynamically according to the fluctuations of electricity price.

QoS-Aware and Load-Balance Routing for IEEE 802.11s Based Neighborhood Area Network in Smart Grid

Monitoring and transforming smart grid (SG) assets in a timely manner is highly desired for emerging smart grid applications. This critically requires the design of a neighborhood area network (NAN) which is capable of providing high-efficiency and reliable two-way last mile communication from meters to other SG domains. For this demand, IEEE 802.11s based wireless mesh network (WMN) is anticipated to be utilized in a NAN as it can provide high scalability, high-speed and cost-effective wireless transmission. In this paper, we propose a NAN QoS-aware and load-balance routing scheme (NQA-LB) based on the default hybrid wireless mesh protocol (HWMP) of IEEE 802.11s, which aims to address multiple QoS requirements from different NAN applications, and guarantee the highly reliability transfer of NAN traffic data towards gateway. With the NQA-LB, various QoS requirements can be satisfied through sufficient differentiated services as well as network congestion is mitigated by achieving load balance between multiple transmission paths. In order to improve the reliability of NQA-LB, we present an EDCA based adaptive priority adjustment scheme, called AP-EDCA, which dynamically adjusts packet's priority to increase the throughput under low load condition and to mitigate the collision under heavy load condition to improve the reliability of applications with high QoS requirements. Extensive simulation experiments demonstrate the superiority of the proposed scheme in terms of packet delivery ratio, end-to-end delay and throughput while satisfies various QoS requirements much better at the same time.

Time‐horizons in the planning and operation of transmission networks: an overview

In the planning and operation of power systems, actions are taken in different processes and time-horizons. The purpose of these actions is to secure a high reliability level. Although the three main processes (grid development, asset management, and system operation) are described in literature, there has been no explicit study on the time-horizons (long-term, mid-term, and short-term) and actual time-scale (decades, years, months, etc.) that these processes focus on. This study aims at making a review of the various activities performed by transmission system operators while reviewing the concept of each time-horizon and methodologies developed in literature. As decisions taken in different time-horizons can influence each other, the interactions and overlapping are discussed.