Voltage depending load models. Validation by voltage step tests

Abstract

This paper presents applications of the Exponential Static Load model used to represent voltage depending loads. This model has been used to represent loads of different types: Industrial, Residential and of Petroleum Extraction Fields.These loads belong to "Sistema Interconectado Patagónico" (SIP), a small power system of 1200 MW of peak load situated in the South of Argentina. Models of several load types have been validated by tests.Tests were made by applying steps to the feeding load voltage. Load voltage sensitivity coefficients were obtained for the different load types tested.Load models validated by tests were used for SIP modal analyses.Index Terms--Load -Load Model -Power system dynamic stability -Simulation -Testing.

Load modeling for fault location in distribution systems with distributed generation

“…Static load models are those which generally can be represented as polynomial functions of the applied voltage [5] [6] [7]. In general, load could be represented as (1).…”

“…On the other hand a special case is presented in (2), which represents the exponential load model [5] [7]. , the load consumes the same current despite fluctuations in voltage magnitude (I cte ).…”

“…The test power system was modeled using elements and the load Z cte from the ATP (Base Case). Next, new load models at the same circuit, but considering those coded using the tool Models of ATP, to obtain the proposed different load models (Z cte , I cte , S cte , 80%I cte plus 20%Z cte [5] and the hybrid model circuit IEEE34 [8]). Fig.…”

“…A common case and caused by the absence of information in the distribution companies, leads to the existence of circuit modeling parameters which are assumed, and therefore may be different to those in the real power system, as the value and load type, among the most important ones. The load models used in most of the applications of fault location are constant impedance [5], [6] and [7]. Considering the actual behavior of the electrical power system, the set of protections and loads, this paper is devoted to analyze their possible influence on the fault location.…”

“…Thus, this paper proposes a comparative analysis between different load models, using the values of the voltage (V) and current (I) measurements, and values of the impedances (Z) as seen from the power substation considering a power distribution system with distributed generation (DG), and also performing different types of shunt faults (single-phase, phase to phase, double phase to ground and three-phase), with different fault resistances (Rf) and varying the load type from a programmed model using the tool Models in ATP (Constant impedance, constant current, constant power, and hybrid models [5], [8]), simulated at different distances from the substation. Additionally, these models were used by fault locators in power distribution systems with distributed generation [9].…”