Please cite this article in press as: K.S. Metallinos, et al., Derivation and evaluation of generic measurement-based dynamic load models,
Electr. Power Syst. Res. (2016), http://dx.doi.org/10.1016/j.epsr.2016.06.022
ARTICLE IN PRESS
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EPSR-4742; No. of Pages 8
Electric Power Systems Research xxx (2016) xxx–xxx
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Electric Power Systems Research
j o ur na l ho mepage: www.elsevier.com/locate/epsr
Derivation and evaluation of generic measurement-based dynamic
load models
Konstantinos S. Metallinos
a
, Theofilos A. Papadopoulos
b,∗
,
Charalambos A. Charalambous
a
a
Department of Electrical and Computer Engineering, Faculty of Engineering, University of Cyprus, PO Box 20537, 1687 Nicosia, Cyprus
b
Power Systems Laboratory, Department of Electrical and Computer Engineering, Democritus University of Thrace, 67100 Xanthi, Greece
a r t i c l e i n f o
Article history:
Received 25 January 2016
Received in revised form 10 April 2016
Accepted 9 June 2016
Available online xxx
Keywords:
Artificial neural networks
Generic models
Load modelling
Measurement-based approach
Nonlinear least-square optimization
Statistical analysis
a b s t r a c t
Online recorded responses can be used for aggregate dynamic load modelling, taking advantage of
the advent of smart grids and the growing installation of phasor measurement units. Although sev-
eral measurement-based dynamic load models have been proposed in the literature, still most network
utilities and system operators take advantage of well-known formulations such as the polynomial and
the exponential recovery models. However, these types of load models are only valid for a specific range
of operating conditions, thus minimizing their applicability and efficiency. This is mainly due to the fact
that the model parameter estimation procedure relies on iterative processes. To this extent, the specific
scope of this paper is to present a comprehensive identification procedure for evaluating load models
under different loading conditions and further to propose two generic modelling approaches that can be
used to derive robust load models that are suitable for dynamic simulations over a wide range. Towards
achieving the scope of this paper, Monte Carlo simulations are used to train and validate the data of
the loading conditions. Finally, several simulations are performed within the DIgSILENT PowerFactory
software to assess the accuracy of the proposed models.
© 2016 Elsevier B.V. All rights reserved.
1. Introduction
Aggregate load models represent the overall coordinated
behaviour of individual electric and electronic components, such as
motors, lighting, electrical appliances, etc. supplied by a common
power system busbar [1]. The impact of the accurate representation
of the steady-state and dynamic characteristics of power system
loads has been long recognized and investigated both at the trans-
mission and distribution network levels, especially considering
studies pertaining to voltage and angular stability [2–6]. Neverthe-
less, in the last decades the increased penetration of motors and
the introduction of new power electronic interfaced loads com-
bined with the need for more operational flexibility as well as the
application of advanced voltage and frequency control strategies
in the distribution network have renewed the scientific interest
on load modelling [7]. Although, detailed load models provide
very accurate load representation, this method requires signifi-
cant computational power and large simulation times for extended
∗
Corresponding author. Tel.: +30 2541079568; fax: +30 2541079568.
E-mail address: thpapad@ee.duth.gr (T.A. Papadopoulos).
networks. However, detailed information of the real load charac-
teristics is rarely available to transmission and distribution utilities.
Thus, load busbars are represented by equivalent models repre-
senting the aggregation of different individual components, such
as static, inductive and capacitive loads, motor driven consumers,
etc. [1,6].
In aggregate load modelling there are two main approaches:
the component-based and the measurement-based [8]. The former
involves the derivation of an aggregate load model based on infor-
mation from its constituent parts, including [8]: (a) the load class
mix (industrial, agricultural, residential), (b) the composition of
each of those classes (heating, cooling, air conditioning, etc.) and
(c) characteristics of each load component related to the corre-
sponding physical characteristics. The advantages of this approach
are that it does not require field-measurements and that it can
be easily applied to different bus substations [1]. However, the
component-based approach is not considered accurate enough to
represent the distinct load characteristics under various system dis-
turbances. On the other hand, in the measurement-based approach
the model parameters are typically defined a priori and their val-
ues are estimated using system identification techniques to fit
the input–output data obtained from measurements. Significant
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