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Reactive power planning or VAR planning is critical to ensure acceptable power quality and system robustness. While addressing var planning, the key issue is optimal allocation i.e. location and size of reactive power sources. Security of power systems is a major concern during contingencies. So, consideration of all plausible contingencies during planning process is important. However, consideration...
Based on the structures and operating principles of the thyristor controlled transformer-type controllable shunt reactor (TCTCSR), the performance of differential protection for this type of devices is studied. For TCTCSR, differential protection may not be reliable or sensible to the turn-to-turn fault and short-circuit fault of thyristors on the control winding (CtrW). To avoid the dead zone of...
In this paper, a trajectory sensitivity method (TSM) is used to estimate parameters of a synchronous generator model suitable for unbalanced conditions which are typical of distribution systems. The current formulation and mechanical equations which represent the synchronous machine have parameters whose value modification cause significant changes in system's output. Trajectory sensitivity method...
Paying for load reductions results in a market, where the amount of resources sold is less than the amount of resources bought. To resolve this imbalance, ISOs must allocate the cost of compensating demand response to those who benefit from reduced LMPs. Current cost allocation methods are based on each energy buyer's load share. In an uncongested network, this results in a “fair” allocation of costs,...
Coordination of ancillary services provided by decentralized power units has become one of the main grid operation challenges because system service responsibilities are increasingly being shifted to medium- and low-voltage networks. This paper describes an implementation method of considered control algorithms on real power units in German mediumvoltage systems in order to maintain the distribution...
With increasing penetration of distributed generation in the distribution networks (DN), the secure and optimal operation of DN has become an important concern. In this paper, an iterative quadratic constrained quadratic programming model to minimize voltage deviations and maximize distributed energy resource (DER) active power output in a three phase unbalanced distribution system is developed. The...
The changes in branch flows and nodal voltages with respect to a change in current injection at a particular node, defined as current transfer distribution factors (CTDF), are useful sensitivity factors for distribution system analysis. In addition, the changes in branch flows due to the outage of a particular branch, defined as branch outage distribution factors (BODF), are useful in many distribution...
In this paper, an approach is proposed to improve linear models adopted in small-signal stability studies using information extracted from measured outputs of real system, as small disturbance data recorded by phasor measurement units (PMU). With this aim, a trajectory sensitivity technique is applied on the mismatch between the output of the simulated model and the response of the real system. Using...
Transient stability constrained optimal power flow (TSCOPF) is a challenging problem of power system. In this paper, TSCOPF is decomposed into three sub-problems, namely transient stability assessment (TSA), the stability constraint constructing and simple TSCOPF. They are solved iteratively to achieve the optimal operation point. In the TSA sub-problem, each contingency is simulated and the stability...
This paper presents an online clustering modeling method for large-scale photovoltaic (PV) power plants. The proposed method utilizes the defined feature distance of inverter control parameters as the clustering index to derive the equivalent PV plant model. Based on the offline parameter database and the online matching method, the feature distance weighted by online parameter sensitivity is obtained...
The potential for cascading failure in power systems adds substantially to overall reliability risk. Monte Carlo sampling can be used with a power system model to estimate this impact, but doing so is computationally expensive. This paper presents a new approach to estimating the risk of large cascading blackouts triggered by multiple contingencies. The method uses a search algorithm (Random Chemistry)...
In this paper, we propose a measurement-based approach to the real-time economic dispatch (ED). The realtime ED is a widely used market scheduling problem seeking to economically balance electricity system supply and demand and provide locational marginal prices (LMPs) while respecting system reliability requirements. The ED is a convex optimization problem with a linear or quadratic objective, typically...
Loading margin sensitivity (LMS) has been widely used in applications in the realm of voltage stability assessment and control. Typically, LMS is derived based on system equilibrium equations near bifurcation and therefore requires full detailed system model and significant computation effort. Availability of phasor measurement units (PMUs) due to the recent development of wide-area monitoring system...
In Part II, we develop an efficient method for generating test cases that ensures early detection of design error. The proposed method uses Particle Swarm Optimization technique for the same. Also, we propose a sensitivity based approach to rectify design errors. The proposed verification technique is applied on standard IEEE test systems and it is seen that it is possible to achieve better accuracy...
This paper presents a new approach to voltage estimation for N−1 contingency analysis. The voltage magnitude after a single line or generator outage is estimated using a voltage sensitivity matrix. The sensitivity matrix is derived using phasor measurements during normal operation. This technique is compared to the traditional voltage sensitivity calculation using the Jacobian of the system, which...
We address the extension of spatiotemporal marginal-cost-based Wholesale Transmission markets to Retail Distribution markets. We formulate the detailed Day Ahead (DA) distribution market clearing problem and solve it for real and reactive power Distribution Location-Marginal-Prices (DLMPs). Using a realistic industrial/commercial/residential distribution network, we obtain the DA market clearing DLMPs...
Accurate load models are necessary to enable multiple power system planning and operation applications. The current day utility practice relies on model parameters that are based on old survey results/tests and often do not accurately capture the behavior of loads across different operating conditions. This results in conservative estimation of loading margin, leading to under-utilization of the assets...
In this paper, the assessment of Financial Losses related to Process Trip (FLPT) due to voltage sags and Long Duration Interruptions (LDI) for the whole distribution network is carried out for different operating conditions in order to highlight the importance of probabilistic assessment of FLPT and in particular of inclusion of Process Immunity Time (PIT) in the evaluation. The FLPT due to voltage...
Net Energy Metering (NEM) is the most common form of compensation for distributed PV and currently 46 states and the District of Columbia have NEM policies. This “easy to understand and implement” policy allows customers with distributed generation to be compensated at the retail electricity rate for any excess generation fed into the grid. However, NEM has recently come under strong criticism from...
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