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Summary form only given.This paper presents results from an analysis of voltage stability following severe contingencies in the PJM system. The analyses involved the use of steady-state (OPF) and short and long-term simulation tools. The results highlight the importance of adequate load modeling in assessing the performance of and solutions to voltage instability. UVLS is shown to be beneficial in...
Summary form only given. In the paper a new approach to adaptive underfrequency load shedding, a procedure for protecting electric power systems from dynamic instability and frequency collapse is presented. It consists of two main stages. In the first stage, the frequency and the rate of frequency change are estimated by the nonrecursive Newton type algorithm. By using the simplest expression of the...
Summary form only given. This paper presents a new method for an optimal measurement placement of phasor measurement units (PMUs) for power system state estimation. The proposed method considers two types of contingency conditions, i.e. single measurement loss and single branch outage, in order to obtain a reliable measurement system. Firstly, the minimum condition number of the normalized measurement...
This paper documents how PacifiCorp is using IEEE 1453 in specific non-arc-furnace applications. The first is its use of the 1453 standard to assess two kinds of unpredictable motor loads. The second is a short discussion of integrating this standard into a handheld electrical pollution screening tool. Finally, the paper gives recommendations on adjusting company flicker standards to accommodate IEEE...
Analysis of faults and protective relay operations is crucial for understanding the fault clearing sequences. Today, this analysis is performed off line and mostly through manual inspection of different data records captured by digital protective relays (DPRs), digital fault recorders (DFRs), Sequence of Events Recorders (SERs), and other substation IEDs. This paper introduces several tools developed...
In this paper, in the background of evolution of power grids in India, establishment of regulatory framework and operational philosophy in vogue, first reliability aspect of long term, mid term as well as short term (operational / outage) planning has been dealt with. Thereafter issues on the day ahead scheduling of generation as associated with real time operation (linking frequency in particular)...
Recent movement pursuing economic efficiency & global environmental protection such as more installation of wind generations in electric power industries has caused increase in power exchange between regions and has made power system operation more challenging due to less operational margins. Generally, rapid cascading tripping of parallel transmission lines or transformers in the early stages...
Faults and disturbances in a utility power system are typically analyzed using recorded data captured by digital fault recorders, digital protective relays, and other intelligent electronic devices. Several steps are involved in the process including communication to the devices, downloading files, viewing data, and protection engineers performing the actual analysis. This paper discusses automated...
Network-centric infrastructure demands robust systems that can respond automatically and dynamically to natural, accidental and deliberate faults, be they on a local scale, regional or national. The effects of weather, from heat waves and cold fronts to hurricanes and ice storms, on the electrical infrastructure are expected to escalate. The consequent power interruptions are an economic hardship...
When a major power system disturbance strikes the power network, protection and are required to stop the power system degradation, restore the system to a normal state, and minimize the impact of the disturbance. In some cases, the present control actions are not designed for a fast-developing disturbance and may be too slow. The paper discusses special protection schemes and new technologies for...
The reliable operation of the interconnected electric system heavily depends upon the accuracy of the dynamic simulation studies. The simulation studies contain models of complex components such as generators, exciter, governors, loads, etc. Many of these models are at best approximate. Hence, the simulation studies must be validated against actual system disturbance from time to time to have confidence...
The Langlois project is the world's first application of the "variable frequency transformer" (VFT) technology, which was successfully commissioned on the Hydro-Quebec TransEnergie (HQTE) system in the spring of 2004. The VFT consists of a rotary transformer, for continuously controllable phase shift, together with a drive system and control that adjust the angle and speed of the rotary...
The author presents a guide for determining the significance of primary governing frequency response (PGFR) to total interconnection reliability using examples from the North American interconnections. Primary governing frequency response assessments based on measurement methods, failure modes, risk contributors, total risk estimation, and sensitivities are presented. Methods to assure adequate primary...
After a fault occurs in a power system, generally some operating information of protective relays and circuit breakers could be obtained. Because protective relays and circuit breakers might improperly operate or fail to operate, and some errors and distortion may exist in data acquisition and communication, as a result uncertainties could be involved in the received information. A fault diagnosis...
Power system restoration decision-making is one of the most important and indispensable issues for ensuring fast power supply restoration to end users. In recent years, the power industry around the globe has been undertaking an in-depth restructuring, and this has led to some new challenges to the problem of power system restoration. In this paper, several important issues related to power system...
The paper discusses a concept of substation data integration for implementation of new automated analysis functions. Proper data integration is the main requirement to enable automation of the analysis and its future extensions. The integrated data concept is making the whole solution transparent to adding new types or product versions of IEDs, as well as new analysis functions. There are several...
Some critical lines can have important impact on the large-scale blackouts and cascading failures in power grid. Based on the newest progress in the field of complex network, a new vulnerability index called weighted line betweenness is proposed as vulnerability index in this paper. The weighted line betweenness of one line is defined as the sum of the loads acted on this line, which are brought by...
This paper presented an alternative technique to improve the security of electric power control systems by using anomaly detection to identify attacks and faults. By using rough sets classification algorithm, a set of rules can be defined. The alternative approach tries to reduce the number of input variables and the number of examples, offering a more compact set of examples in order to fix the rules...
This paper discusses the latest developments in wide-area frequency-based event location using FNET. FNET, meaning ldquoInternet based frequency monitoring networkrdquo, is a low cost and quickly deployable wide-area frequency measurement system with high dynamic accuracy. This project demonstrated the feasibility of using information from FNET to estimate the location of events in the electric grid...
The measured impedance trajectory changing with fault resistance during multi-phase faults and the reasons that fault resistance may cause unwanted impedance relay operations in two-source systems were analyzed in this paper. To improve the impedance relay adaptive ability and reliability during three phase fault, a combined phase-to-phase impedance relay based on the measured impedance trajectory...
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