2014 International Conference on Mechanical Engineering, Autoation and Control Systes (MEACS)
Technique for Field Data Based Identification of
Static Polynomial Load Model
Natalia L. Batseva, Aleksey V. Pankratov, Yuriy V.
Khrushchev, Anton V. Prokhorov
Department of Electrical Networks and Engineering
Tomsk Polytechnic University
Tomsk, Russia
davek-19K@yandex.ru
Abstract- the aim of the research is to develop and test
technique for obtaining load static characteristics of large
industrial enterprise. The research is initiated because the
available data about Russian power system load have become
outdated due to the change of power system structure, load
content and behavior. At the same time the existing methods do
not properly solve the problem of ill-conditioned data which is
essential for such stochastic system as electrical load. The
solution of this problem can be provided only on the basis of
multiple experiments accounting different operating conditions of
power system. The results of the first stage of such experimental
work scheduled for the next several years by Russian System
Operator is presented in the paper. To collect the data required
for developing and testing of new multistage technique for
identification of static polynomial load model, an active
experiment was conducted. The proposed technique combines the
successive approximation method and least-square method for
filtering ill-conditioned data and estimation of polynomial model
parameters. The obtained results confirm the efficiency of the
proposed technique.
Keywords- load static characteristic; voltage; active power;
reactive power; power system; active periment.
I. INTRODUCTION
One of the main tasks that are solved for energy market
operation is evaluation of transmission capacity limits. An
accurate solution of this task is extremely important since raw
estimations may lead to overstanding of operating margins and
as a result to undershooting of power system efficiency
improvement capabilities.
It is a well-known fact that accuracy of transmission
capacity limits estimation is significantly dependent on the
choice of electrical load simulation approach. Simulation of
electrical load is complicated when it conces a large power
system state estimation tasks because each power system node
consists of a large number of power consumers with different
capacity, parameters, load factor and operating conditions.
The load simulation task became of great importance aſter
several large outages over the world, when the lack of accurate
information about characteristics of electrical load led to loss
of power system stability, complication of load restoration in
post fault conditions and significant damage [1-3].
Alexander S. Tavlintsev
Department of Automated Electrical Systems
Ural Federal University
Yekaterinburg, Russia
The increasing interest of Russian electrical utilities to the
improvement of electrical load model performance is
connected with aging of data about load static characteristics
that had been estimated last time more than twenty years ago.
The precise attention to the static characteristic can be
explained by the fact that they are used in power system
soſtware intended for solution of dispatching control and
wholesale electricity market tasks [4].
II. PERFORMANCE OF EXPERIMENT
This paper is based on results of active experiment that
was conducted for consumers of 35/6 kV substation of a cable
factory to identi the parameters of voltage dependent static
characteristics of a load connected to 6 kV busbar. Experiment
consisted of changing the position of on-load tap changer of
10 MVA power transformer supplying the load.
The experiment was conducted under the following
conditions:
• The equency was stabilized and approximately equal
to the rated value of 50 Hz.
• The available range of voltage change during
experiment was not less than IS % of the rated voltage
value Urated (the maximum voltage value is limited by
power equipment operating limits and the minimum
value was limited by the load stability margin).
• The measurements were done with multichannel
portable power analyzer AR5 CIRCUTOR which
allowed recordkeeping and transfer the data to the
personal computer. The analyzer was connected to the
voltage and cuent measurement transformers with
accuracy classes of 0.5 and O.2S respectively.
Three phase voltage Ui, active Pi and reactive Qi power
values were obtained and stored in arrays for processing.
III. TECIQUE OF DATA PROCESSING
Voltage dependent static load characteristics are the
dependencies of load active or reactive power on applied
voltage in steady state conditions. These characteristics are
most commonly performed as polynomial functions:
978-1-4799-6221-1/14/$31.00 ©2014 IEEE