International industry practice on power system load modelling

Abstract

Power system load modelling is a mature and generally well researched area which, as many other in electrical power engineering at the present time, is going through a period of renewed interest in both industry and academia. This interest is fuelled by the appearance of new non-conventional types of loads (power electronicbased, or interfaced through power electronics) and requirements to operate modern electric power systems with increased penetration of non-conventional and mostly intermittent types of generation in a safe and secure manner. As a response to this renewed interest, in February 2010 CIGRE established working group C4.605: Modelling and aggregation of loads in flexible power networks. One of the first tasks of the working group was to identify current international industry practice on load modelling for static and dynamic power system studies. For that purpose, a questionnaire was developed and distributed during the summer/autumn of 2010 to more than 160 utilities and system operators in over 50 countries on five continents. This paper summarizes some of the key findings from about 100 responses to the questionnaire received by September 2011 and identifies prevalent types of load models used as well as typical values of their parameters.

Recommended Parameter Values and Ranges of Most Frequently Used Static Load Models

“…Numerous data and models presented in sections Overview of Existing Load Models and Results of the International Survey on Load Modelling of this report, related paper [11], and other available literature [12]- [15] and [16]- [24] are analysed and discussed in this paper. In order to draw proper conclusions and recommendations for power system studies, the parameters of different electrical devices are grouped in types in this paper and first analysed separately, and then as the contributing parts of aggregate demands of different load classes and aggregate system loads of different regions of the world.…”

“…Considering that the number of currently used load models is significant, the paper summarizes only the most frequently used load models, especially these for which parameters can be found in available literature and these obtained from an international survey on load modelling practices in [10] and [11], completed by around utilities and transmission system operators (TSOs) from around the World. Accordingly, this paper specifies typical parameter values/ranges of commonly used models, of voltage dependent, and voltage and frequency dependent exponential load models, identified on the basis of the analysis of numerous data.…”

Investigation of Load Frequency Relief From Field Measurements and Its Impact on Contingency Reserve Evaluation

“…It is to be articulated that these types of models are widely used in Australia and many other countries around the world [23]. According to these models, both real and reactive components of loads are assumed to have a dependence on voltage (V) and frequency.…”

“…According to these models, both real and reactive components of loads are assumed to have a dependence on voltage (V) and frequency. Hence, real power (P) and reactive power (Q) can be expressed by (1) and (2) [22,23] respectively.…”

“…np1 and nq1) indicate the nature of loads, which ultimately helps in load modelling. An accurate modelling of system loads plays a vital role in power system studies related to stability, planning, operation and control [23]. Different values of np1 and nq1 that determine the characteristics of loads are summarised as follows [22].…”