Planning for controllable network devices in power transmission systems

The full capacity of the existing transmission lines is often underutilized due to the system stability requirements. Controllable network devices represent the effective means of improving the system stability, and their deployment allows better use of the existing transmission facilities and can help to avoid construction of new lines. This dissertation addresses system analysis and modeling of controllable network devices. Transient angle stability is one of the major requirements limiting transfer capability of the power transmission systems. The theoretical concepts of transient angle controllability using controllable network devices are considered in this dissertation. The main results are derived for a general transmission network structure and applied to series and shunt compensators as well as braking resistors. The proposed approach allows to quantify controllability and to relate it to the control device size, type and location in the transmission network. Transient stability controllers are needed to maximize the device effect on the transient angle stability enhancement. The transient stability controller functional structure is discussed and the design requirements for each component are specified. The examples of controller designs are presented. Emerging technologies such as Thyristor-Controlled Series Compensators and Synchronous Voltage Sources offer superior control capabilities and performance characteristics as compared to conventional compensators. Unlike conventional compensators, the new controllable network devices are very complex dynamical systems and require more comprehensive modeling for time-domain studies and controller designs. Detailed models of a Thyristor-Controlled Series Compensator and a Synchronous Voltage Source for powerflow, transient stability, and electro-magnetic transient studies are presented. Finally, a detailed planning study for increasing transfer capability of the Montana transmission system using controlled series compensation is presented. A variety of design and performance requirements is considered in this study, which makes it a useful reference for similar planning projects

A Simple Computation and Visualization of Voltage Stability Power Margins in Real-Time

peer reviewedThis paper introduces a simple method to monitor power system voltage stability conditions in real-time. The method is based on the concept of Voltage Instability Predictor (VIP). The essence of the method is a simple computation of a voltage stability boundary based on VIP derived quantities. The stability boundary is assumed as a parabolic equation in the P-Q plane identified using measurements collected at a specific substation, transmission path, or load center. The computed stability boundary is further visualized in a P-Q plane, together with a point representing the current operating conditions, and generally re-computed as soon as the new set of measurements is collected (preferably at high rates using phasor measurement units). Simplicity and easy interpretation of the results brings this method as a useful tool to increase system operator situational awareness. Supporting results are provided using relatively big test system (52 bus Nordic test system) and a real-life system (a portion of the North-West USA system)

Load Monitoring CEC/LMTF Load Research Program

This white paper addresses the needs, options, current practices of load monitoring. Recommendations on load monitoring applications and future directions are also presented

Load Composition Analysis in Support of the NERC Load Modeling Task Force 2019-2020 Field Test of the Composite Load Model

In 2015, NERC’s reliability standards were revised to require the use of dynamic load models in transmission planning studies. To comply with the standards, planners must use load models that explicitly represent the dynamic behavior of the different constituents of load at each load bus within their transmission planning models. The most important of these constituents are motor-driven and power electronics-based loads. Collectively, these representations are known as composite load models. In anticipation of the compliance date for the new standards, NERC’s Load Modeling Task Force (LMTF), in 2019, initiated a field test of composite load models involving the regional reliability planning entities. In support of the field test, DOE and BPA researchers developed region-specific composite load models that could be assigned to each non-industrial load bus in the planning models for each of the North American interconnections. Separate models were developed for each hour of a summer peak day, a winter peak day, and a spring light-load day. This report is the technical documentation for the load composition analysis that was conducted to develop these non-industrial composite load models

Load Composition Analysis in Support of the NERC Load Modeling Task Force 2019-2020 Field Test of the Composite Load Model

In 2015, NERC’s reliability standards were revised to require the use of dynamic load models in transmission planning studies. To comply with the standards, planners must use load models that explicitly represent the dynamic behavior of the different constituents of load at each load bus within their transmission planning models. The most important of these constituents are motor-driven and power electronics-based loads. Collectively, these representations are known as composite load models. In anticipation of the compliance date for the new standards, NERC’s Load Modeling Task Force (LMTF), in 2019, initiated a field test of composite load models involving the regional reliability planning entities. In support of the field test, DOE and BPA researchers developed region-specific composite load models that could be assigned to each non-industrial load bus in the planning models for each of the North American interconnections. Separate models were developed for each hour of a summer peak day, a winter peak day, and a spring light-load day. This report is the technical documentation for the load composition analysis that was conducted to develop these non-industrial composite load models

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

peer reviewedAS 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. This article describes simple and accurate methodologies based on real-time measurement— and independent of the system model—designed for tracking both slowdeveloping and transient voltage stability conditions under various and changing system configurations. Tests with real-time supervisory control and data acquisition (SCADA) and PMU data, as well as data from comprehensive simulation studies, from the Bonneville Power Administration (BPA) and Southern California Edison (SCE) systems show very accurate detection as the system is approaching voltage instability. The calculated reactive power margin and other indices are easily visualized for operator awareness. For quickly developing disturbances, they allow the initiation of fast control and protection actions. This methodology also discriminates well between FIDVR and short-term voltage instability. Finally, a tool for properly modeling the complex voltage phenomena is described