Dmitry Kosterev

Load modeling in power system studies: WECC progress update

This paper provides an update on a composite load model development in Western Electricity Coordinating Council (WECC). A composite load model structure is described. The two salient features of the new load model are: (a) the model recognizes electrical distance between the transmission bus and the end-uses and (b) the model represents the diversity in composition and dynamic characteristics of various electrical end-uses. The load model data includes (a) data for a distribution equivalent model, (b) load component model data and (c) load component fractions. The paper presents tests and modeling of various electrical end-uses. The paper in particular focuses on modeling compressor motors in single-phase air-conditioners. Load composition methodology is also discussed. The model structure was implemented and tested in a production-level grid simulator.

Hydro turbine-governor model validation in pacific northwest

This paper presents an approach for generator model validation based on the measurements taken at the point of interconnection. The approach is initially applied for The Dalles powerhouse, where the simulated and actual governor responses were found different. Governor tests and monitoring were performed and resulted in model revisions. The approach also resulted in improvements of John Day turbine-governor models. Grand Coulee governor response was validated and found adequate. Based on the project experience, a process for generator model validation is proposed.

Generator dynamic model validation and parameter calibration using phasor measurements at the point of connection

Summary form only given. Power system model quality is key to safe and reliable electricity delivery. In this paper, a novel method using disturbance data recorded by phasor measurement units (PMUs) is proposed to improve the integrity of dynamic models, which consists of both model validation and model parameter identification. In the model validation step, event playback is applied to simulate the models response for a rigorous comparison with measured response captured by PMUs. A large mismatch indicates model deficiency. In the parameter identification step, an automatic calibration method using the extended Kalman filter (EKF) techniques and trajectory sensitivity analysis is formulated to save significant effort and time from manual tuning. Case studies are presented to demonstrate that the proposed method has adequate performance for model validation and parameter calibration in terms of accuracy, good convergence speed and robustness with respect to measurement noises. The proposed method is cost-effective and complements traditional equipment testing for improving dynamic model quality.

Application of extended Kalman filter techniques for dynamic model parameter calibration

Phasor measurement has previously been used for sub-system model validation, which enables rigorous comparison of model simulation and recorded dynamics and facilitates identification of problematic model components. Recent work extends the sub-system model validation approach with a focus on how model parameters may be calibrated to match recorded dynamics. In this paper, a calibration method using Extended Kalman Filter (EKF) technique is proposed. This paper presents the formulation as well as case studies to show the validity of the EKF-based parameter calibration method. The proposed calibration method is expected to be a cost-effective means complementary to traditional equipment testing for improving dynamic model quality.

Load Modeling in WECC

This paper presents an update on the load model development undertaken by the utilities and grid operators in the Western Electricity Coordinating Council (WECC). The paper describes the driving forces for accurate load modeling in WECC. The structure of the proposed composite load model is presented. The paper also discusses the need for special modeling of compressor motors in single-phase air-conditioners and refrigerators. The paper describes the data requirements for the new composite load model and outlines the structure of the load model data tool. The issues related to load model validation are discussed. Finally, the paper provides expectations of the impact that the load model will have on the system performance studies

PDCI damping control analysis for the western North American power system

Transmission capacity in the western North American power system (termed the wNAPS) is often limited by poorly-damped electromechanical oscillations. To date, the primary damping controllers applied in the wNAPS are via generator controls using localized feedback signals. Such controls have limited effectiveness for inter-area modes. Recent development of reliable real-time wide-area measurement systems (WAMS) has enabled the potential for large-scale damping control approaches. One such approach is feedback modulation of the Pacific DC Intertie (PDCI). This paper summarizes simulation results from a study to evaluate PDCI damping control in the wNAPS. This includes developing a safe and effective control strategy, quantifying potential improved damping, and conducting open-loop actual-system probing tests.

See It Fast to Keep Calm: Real-Time Voltage Control Under Stressed Conditions

As the electrical utility industry addresses energy and environmental needs through greater use of renewable energy, storage, and other technologies, power systems are becoming more complex and stressed. Increased dynamic changes that require improvements in real-time monitoring, protection, and control increase the complexity of managing modern grids. In an effort to ensure the secure operation of power systems, more attention is being given to voltage management. Voltage management includes addressing voltage stability and fault-induced delayed voltage recovery (FIDVR) phenomena. Deployment of phasor measurement unit (PMU) technology, in combination with recently developed methodologies for tracking voltage behavior, has resulted in improved real-time voltage monitoring, protection, and control.

Validation of power system models

Since models form the basis for most power system studies, power system model validation is an essential procedure for maintaining system security and reliability. The procedure may be viewed as a “top-down” approach to model verification; comparisons with measured data indicate the quality of the overall model. Analysis of the differences demonstrates which subsystem component models need to be revalidated. Numerous examples are presented to illustrate the use and importance of system model validation.

Phasor modeling approach for single phase A/C motors

In this paper we present results of a development of a single-phase induction motor model using dynamic phasors. This phasor model is intended to represent the compressor portion of the behavior of a typical residential air conditioner load. A review of the model is presented. This model is then used to validate data from laboratory tests of air conditioners at Bonneville Power Administration. The results show that the model accurately captures the relations between voltage, frequency, active power, and reactive power. Furthermore, the model reproduces motor stall conditions, both the onset and severity of the stall. We expect that the use of this load model will improve our ability to anticipate voltage and transient stability problems in the power grid.

Results of residential air conditioner testing in WECC

This paper summarizes the key results of testing work performed by three organizations (EPRI, SCE, and BPA) on a total of twenty seven air conditioning units in order to better understand and thus characterize their behavior for power system simulations. The diversity of the tested air conditioner units included sizes (tonnage), compressor technology (reciprocating and scroll), type of refrigerant (R-22 and R-410A), efficiencies (between 10 and 13 SEER), and vintage (new and old). A common test plan was developed by the three organizations. The tests were then performed independently by each of the three organizations. The EPRI work was sponsored by APS and SRP. This effort was part of the current load modeling effort going on in WECC under the load modeling task force. The key findings of this work are presented here together with a description of the testing methodology. All three organizations found very similar results despite testing a variety of different sizes and manufacturer units. The key results presented are associated with the stalling behavior of the units at different outdoor temperatures, the behavior of thermal overload tripping, contactor dropout, and the behavior of the units in response to different emulated types of system events.