Distribution system state estimation
migdat hodzic1995, IEEE Transactions on Power Systems
Sign up for access to the world's latest research
checkGet notified about relevant papers
checkSave papers to use in your research
checkJoin the discussion with peers
checkTrack your impact
Abstract
A three-phase distribution system state estimation algorithm is proposed in this paper. Normal equation method is used to compute the real-time states of distribution systems modeled by their actual a-b-c phases. A current based formulation is introduced and compared with other formulations. Observability analysis for the proposed distribution system state estimation is discussed. Test results indicate that the normal equation method is applicable to the distribution system state estimation and the current based rectangular form formulation is suitable for this application.
Related papers
New Formulation for Distribution System State Estimation
2012 VI Andean Region International Conference, 2012
This paper presents a new formulation for system state estimation of passive electric distribution networks. The fundamental idea discussed here is how to obtain the state of the system at maximum demand condition using three sources of information: 1) a quasi-symmetric matrix called TRX representing network structure and topology, 2) power measurements at main feeder disconnection devices and reclosers installed in the network, and 3) Energy measurements and estimated load curve of aggregate users at distribution transformers. The method is formulated with real variables for single-phase positive sequence radially operated networks. Results of the application of proposed methodology are presented using the well known IEEE 4-Node test system.
A Review on Distribution System State Estimation Techniques
2018
Transition to a sustainable energy environment results in aggregated generator and load dynamics in the distribution network. State estimation is a key function in building adequate network models for on-line monitoring and analyses. The requirements of Distribution System State Estimation (DSSE) is becoming stringent because of the needs of new system modeling and operation practices associated with integration of distributed energy resources and the adoption of advanced technologies in distribution network. This paper summarizes the state of the art technology, major hurdles and challenges in DSSE development. The opportunities, paradigm shift and future research directions that could facilitate the need of DSSE are discussed.
A Review on Distribution System State Estimation
IEEE Transactions on Power Systems, 2017
Transition to a sustainable energy environment results in aggregated generator and load dynamics in the distribution network. State estimation is a key function in building adequate network models for online monitoring and analyzes. The requirements of distribution system state estimation (DSSE) is becoming stringent because of the needs of new system modeling and operation practices associated with integration of distributed energy resources and the adoption of advanced technologies in distribution network. This paper summarizes the state-of-the-art technology, major hurdles, and challenges in DSSE development. The opportunities, paradigm shift, and future research directions that could facilitate the need of DSSE are discussed.
Real-life distribution state estimation integrated in the distribution management system
International Transactions on Electrical Energy Systems, 2016
The article presents a robust real-life distribution state estimation (DSE) that is integrated in the distribution management system. The DSE optimization procedure is developed in full accordance with the nature of distribution networks and their back/forward sweep-based load flow calculation. Thus, DSE is conceptually different from the traditional (transmission) state estimation. The article proves that the proposed DSE, even with relatively low level of telemetry and large dimensions of distribution networks, not only is possible as a function with value of its own but also provides a foundation for other important distribution management system functions. The procedure is the result of both research studies carried out in the last several years and real-life applications worldwide. Thus, this article offers DSE as an industrygrade product.
Three-Phase State Estimation of a Low-Voltage Distribution Network with Kalman Filter
Energies
The state estimation of distribution networks has long been considered a challenging task for the reduced availability of real-time measures with respect to the transmission network case. This issue is expected to be improved by the deployment of modern smart meters that can be polled at relatively short time intervals. On the other hand, the management of the information coming from many heterogeneous meters still poses major issues. If low-voltage distribution systems are of interest, a three-phase formulation should be employed for the state estimation due to the typical load imbalance. Moreover, smart meter data may not be perfectly synchronized. This paper presents the implementation of a three-phase state estimation algorithm of a real portion of a low-voltage distribution network with distributed generation equipped with smart meters. The paper compares the typical state estimation algorithm that implements the weighted least squares method with an algorithm based on an itera...
Distribution state estimation for smart distribution system
PowerTech (POWERTECH), 2013 IEEE Grenoble, 2013
With the penetration of distributed generations into distribution network, more distribution automation will be required. Therefore, smart grid technologies become more important aspect in electric power system. Real-time monitoring of the network is a main step to achieve smart grid technologies. Hence, distribution state estimation becomes more essential for real-time monitoring of traditional distribution network. This paper addresses a distribution state estimation method to achieve smart grid technologies in a traditional distribution network. It will involve exploring distribution state estimation method with minimum number of real-time measurement devices. Therefore, pseudo measurements are applied to address the limitation of the number of real-time measurements. In addition, by incorporating load model, state estimation results are improved and enhanced. In this paper, dynamic aspect of distribution state estimation has been developed for smart grid purposes. The proposed distribution state estimation results are justified with PSCAD/EMTDC software to verify and validate the system state variables
Robust pseudo-measurement modeling for three-phase distribution systems state estimation
Electric Power Systems Research, 2020
Trending integration of distributed energy resources calls for state estimation at the distribution level for providing reliable power systems information. In contrast to transmission systems, distribution systems are sparsely monitored, and consequently difficult to estimate states. To address measurement scarcity problem in distribution systems, this paper proposes a distribution system state estimation framework that relies on robust pseudo-measurement modeling. User-level metering data is used to train gradient boosting tree models for generating pseudo-measurements. A ladder iterative state estimator is then applied on the pseudo-measurements to solve for system states. Simulation studies are performed on the IEEE 13-bus and 123-bus test feeders. Numerical results demonstrate that the proposed state estimation scheme outperform two benchmark approaches in terms of accuracy (error), consistency (error variance) and robustness (high accuracy subject to load changes).
A three-phase algorithm for state estimation in power distribution feeders based on the powers summation load flow method
Electric Power Systems Research, 2015
State estimation approaches for use in transmission systems are common in the literature, however, there are few algorithms intended for distribution systems. This occurs, mainly, due to the small amount of measurement data available in real time and topological complexity of these systems. In this context, this paper proposes a new three-phase state estimation algorithm for radial distribution feeders, which is based on adjustment of loads from a dynamic utilization and imbalance factors, in order to model pseudomeasurements of powers, and take into account the imbalance of loads, frequently presents in feeders. The method performs the estimation by section, starting from the substation toward the loads, where estimated quantities in a section are used as pseudo-measurements to estimate the subsequent section. This procedure provides a computational optimization for real-time methodology presented here. Tests were performed in distribution feeders from a Brazilian power company and the results show satisfactory performance of developed state estimator in respect to adjustment of estimated values compared with corresponding real-time measured quantities.
Distribution system state estimation-A step towards smart grid
Renewable and Sustainable Energy Reviews
State estimation (SE) is well-established at the transmission system level of the electricity grid, where it has been in use for the last few decades and is a most vital component of energy management systems employed in the monitoring and control centers of electric transmission systems. However, its use for the monitoring and control of power distribution systems (DSs) has not yet been widely implemented because DSs have been majorly passive with uni-directional power flows. This scenario is now changing with the advent of smart grid, which is changing the nature of electric distribution networks by embracing more dispersed generation, demand responsive loads, and measurements devices with different data rates. Thus, the development of distribution system state estimation (DSSE) tool is inevitable for the implementation of protection, optimization, and control techniques, and various other features envisioned by the smart grid concept. Due to the inherent characteristics of DS different from those of transmission systems, transmission system state estimation (TSSE) is not applicable directly to distribution systems. This paper is an attempt to present the state-of-the-art on distribution system state estimation as an enabler function for smart grid features. It broadly reviews the development of DSSE, and challenges faced by its development, and 2 33 various DSSE algorithms, as well as identifies some future research lines for DSSE.
Choice of estimator for distribution system state estimation
IET Generation, Transmission & Distribution, 2009
In this study, a statistical framework is introduced to assess the suitability of various state estimation (SE) methodologies for the purpose of distribution system state estimation (DSSE). The existing algorithms adopted in the transmission system SE are reconfigured for the distribution system. The performance of three SE algorithms has been examined and discussed in standard 12-bus and 95-bus UK-GDS network models.
Related papers
A new model for real-time state estimation in distribution systems
… on Electricity Distribution …, 2003
State Estimation Techniques for Electric Power Distribution Systems
—This paper provides a survey of techniques for state estimation in electric power distribution systems. While state estimation has been applied in the monitoring and control of electricity transmission systems for several decades, it has not been widely implemented in distribution grids to date. However, with the recent drive towards more actively-managed, intelligent power distribution networks (" smart grids ") and the improvements in monitoring and communications infrastructure , Distribution System State Estimation (DSSE) has been receiving significant research interest. DSSE presents a number of unique challenges due to the characteristics of distribution grids, and many of the well-established methods used in transmission systems cannot be applied directly. This paper provides a detailed survey of the available methods for DSSE, reviewing around 70 papers from the major journals. In addition, it discusses the potential for applying Advanced Metering Infrastructure (AMI) data and computational intelligence methods in DSSE.
Real-Time Monitoring of Distribution System Based on State Estimation
IEEE Transactions on Instrumentation and Measurement, 2016
The development of the smart grid requires new monitoring systems able to support automation functionalities to control Distributed Energy Resources (DERs). A real time Distribution System State Estimator (DSSE) integrated with bad data processor is presented in this work as a key element of the monitoring system. The developed DSSE is optimized for real time applications, particularly for computational efficiency, numerical stability and robustness against measurements with large error. The DSSE is localized within an automation platform, that performs monitoring and control at substation level, from which the requirements for monitoring are derived. DSSEs located in different automation platform may be coordinated through Multi Area algorithms, improving solution's time efficiency and robustness, but maintaining acceptable accuracy levels. The performance of real time DSSE, both for single and multi-area is analyzed and discussed by means of real time simulations performed in distribution Medium Voltage (MV) and Low Voltage (LV) networks.
On line State Estimator for Three Phase Active Distribution Networks Displayed on Geographic Information System
To improve the operating performance of a distribution network, on line monitoring is required. For this purpose, sensors (metering devices) are installed. To reduce the number of sensors, state estimation approach can be used to estimate the voltage of buses which do not have sensors. This paper proposes online state estimator for three phase active distribution networks using Neural Network and displayed the results on Geographic Information System (GIS). Neural Network based state estimation is used to estimate the bus voltages by using learning approach from power flow patterns. K-matrix three phase distribution power flow is used in this method as an analytical tool. The K-matrix approach is combined with Particle Swarm Optimization (PSO) in handling a Distributed Generation (DG) which is operated as a voltage controlled (PV) bus. The test results show that the proposed method can reduce the number of sensors significantly (almost 50%)
Development and Testing of a Branch Current Based Distribution System State Estimator
The recent increase of distributed generation has forced many distribution network operators to develop distribution automation and active network management. Many active distribution network management functions need accurate real-time estimates of the network state. In this paper, a distribution network state estimation algorithm is developed and used in conjunction with coordinated voltage control. The state estimator utilizes equality constrained weighted least squares optimization and includes bad data detection. The state estimator is tested with MATLAB simulations, real-time digital simulator and in a real distribution network.
An Augmented Branch Current Formulation for State Estimation in Distribution Systems
2021 IEEE 11th International Workshop on Applied Measurements for Power Systems (AMPS), 2021
The monitoring of distribution systems via ad hoc state estimation techniques is essential to provide system awareness to distribution system operators and to enable advanced control functionalities. When estimating the operating conditions of the system, it is important not only to identify the state of the grid, but also to determine the confidence interval around the obtained estimates. The final accuracy of the state estimation results depends on the uncertainties associated to both the input measurements and the underlying grid model. This paper presents a branch-current-based state estimation formulation that includes the network parameters as additional state variables to be estimated in the estimation process. Available data associated with network parameters are treated as generic inputs with an associated uncertainty and their knowledge can be refined via the state estimation procedure. In this way, the proposed framework allows considering the accuracy characteristics of both measurements and grid model when extracting the output uncertainty of the estimates. Simulations on a sample distribution grid prove the validity of the proposed model and show the importance of considering the grid parameters uncertainties for determining the final state estimates together with their uncertainty.
A Review on State Estimation Techniques in Active Distribution Networks: Existing Practices and Their Challenges
Sustainability, 2022
This paper provides a comprehensive review of distribution system state estimation in terms of basic definition, different methods, and their application. In the last few years, the operation of distribution networks has been influenced by the installation of distributed generations. In order to control and manage an active distribution network’s performance, distribution system state estimation methods are introduced. A transmission system state estimation cannot be used directly in distribution networks since transmission and distribution networks are different due to topology configuration, the number of buses, line parameters, and the number of measurement instruments. So, the proper state estimation algorithms should be proposed according to the main distribution network features. Accuracy, computational efficiency, and practical implications should be considered in the designing of distribution state estimation techniques since technical issues and wrong decisions could emerge...
Review of Trends in State Estimation of Power Distribution Networks
Journal of Power and Energy Engineering, 2020
Distribution network state estimation provided complete and reliable information for the distribution management system (DMS) and was a prerequisite for other advanced management and control applications in the power distribution network. This paper first introduced the basic principles of the state estimation algorithm and sorted out the research status of the distribution network state estimation from least squares, gross error resistance etc. Finally, this paper summarized the key problems faced by the high-dimensional multi-power flow active distribution network state estimation and discussed prospects for future research hotspots and developments.
Distribution System State Estimation Model Using a Reduced Quasi-Symmetric Impedance Matrix
—This paper presents a novel formulation of the Distribution System State Estimation (DSSE) optimization model. For a given electric three-phase circuit feeder, network models are built using a quasi-symmetric impedance matrix TRX representing the entire structure and topology of the radial network. As a key contribution , the state variables of demands and generators connected to large-scale distribution grids are obtained by using a convenient matrix reduction technique. As a result, the size of the optimization problem is considerably reduced with respect to the jacobian formulation by considering radial and weakly meshed exploitation and elimination of interconnecting nodes. Results and comparative analysis are presented using the IEEE 4-, 13-, 37-, 123-, and 8500-node test systems.
A new formulation of state estimation in distribution systems including demand and generation states
2015 IEEE Eindhoven PowerTech, 2015
Distribution system state estimation faces a major difficulty: the lack of real-time measurements. This imposes to add information, usually pseudo-measurements from historical data. This paper proposes a different, novel formulation of state estimation relying on the classification of loads into components (e.g. residential, commercial, etc.) and accounting for dispersed generation. The approach "by-passes" the use of pseudomeasurements by expressing the medium-voltage bus injections as functions of a small number of active power components at low-voltage level, treated as additional state variables. The injections at medium-voltage buses become equality constraints. A procedure to identify the above functions is detailed, which takes advantage of data collected by smart meters.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.