Load Flow Sensitivity Research Articles

HVDC Transmission Placement Study to Increase Critical Clearing Time Using Sensitivity Analysis

Stability is the ability to go back to ordinary conditions after an interruption. Power transfer using an AC transmission system has some stability issues. Fast modulation of the HVDC transmission can escalate the transient stability of interconnected power systems thereby increasing the CCT. To calculate load flow sensitivity, use the load flow sensitivity analysis command in Powerfactory 15.1. The variable considered in this research is dφ/dP. In this paper, we will discuss the use of sensitivity analysis to specify the location of the HVDC transmission to increase the CCT value. By taking several samples that have high sensitivity values,namely channels 8-9 to 7-8 with an average cct change value of 0.555 s, mediumvalues, channels 5-8 to 9-6 have an average cct change of 0.234 s, and low fromchannels 6-4 to 9-4 with an average change of 0.109 s. The data above shows thata channel with a large sensitivity value will provide a higher increase in cct valuecomparedwith a low sensitivityvaluewhen paired with an HVDC.

Alternative Approaches for Analysing the Impact of Distributed Generation on Shunt Compensated Radial Medium Voltage Networks

This paper investigates the impact of distributed generation (DG) on the output of shunt capacitors using power system analysis (PSA) tool DIgSILENT Powerfactory. The study then investigates two non-PSA techniques and one alternative PSA technique which makes use of Load Flow Sensitivities (LFS) to perform voltage assessment and assess the effect of DG on medium voltage (MV) shunt capacitors. The use of non-PSA techniques is crucial to utilities in developing countries like those found in sub-Saharan Africa. Globally the use of PSA tools are part of standard practice and the use of LFS can be shown to reduce the steps involved in voltage analysis and provides additional benefit to using PSA tools. In this paper, authors use South African MV capacitor placement methodologies implemented by the national energy utility, Eskom.

Stability analysis of power system loads with recovery dynamics

This paper develops an approach to stability analysis for long-term dynamics of load systems. A novel approach to modelling aggregate dynamic load is used. This leads naturally to differential-algebraic models and an analytical basis which closely ties together static (load flow sensitivity) and dynamic (small and large disturbance) criteria for stability. Further theoretical insights are seen to be possible. A series of examples illustrates the results.

Analysis of the load flow behaviour near a Jacobian singularity

New theoretical results above the behavior of the load flow solution near a Jacobian singularity are presented. The principal result is the derivation of an analytic closed-form relation between the specified injections and the resulting voltages in the neighborhood of a singularity. This result is a companion to the conventional load flow sensitivity analysis which is valid only if the operating point is not at a Jacobian singularity. The new closed-form relation derived is theoretically important since it can predict and explain the main load flow phenomena observed through simulation analysis near a singularity. These are: the nonexistence of solutions for certain injection changes, the bifurcation of the voltages into two nearby solutions, the sudden collapse of voltages for small injection changes, and the nature of the collapse, that is, which buses are more susceptible to the collapse. Numerical simulations support the validity of the theoretical result by comparing the closed-form analytic relation near a singularity with exact load flow simulations. >