LATVIAN JOURNAL of PHYSICS and
TECHNICAL SCIENCES
Nr. 1-2008
PHYSICAL AND TECHNICAL PROBLEMS OF ENERGETICS
Barkāns J., Žalostība D.
View of climate changes based on the wavelet analysis of solar intensity
Klāvs G., Kudreņickis I., Krūgs M.
Assessment of the policy of sustainable biomass-based heat energy supply at the municipal
level
Survilo J.
Application of apparent impedance method at variable specific resistance of phase conductor
Ney R., Ekmanis Yu., Michna J., Zeltins N.
Energy use and related risk management problems in CEE countries
Krišāns Z., Oļeiņikova I., Mutule A., Kalpiņa A.
Method of switchyard types selection for transmission networks
SOLID STATE PHYSICS
Martuzans B., Skryl Yu.
Abnormal influence of ions on chock-induced polarization in binary electrolytes
Page 1
of 4
LATVIAN JOURNAL of PHYSICS and
TECHNICAL SCIENCES
VIEW OF CLIMATE CHANGES BASED ON THE WAVELET ANALYSIS OF SOLAR
INTENSITY
J. Barkāns, D. Žalostība
Riga Technical University, the Institute of Power Engineering,
1 Kronvalda Blvd., Riga LV-1010, LATVIA
The view of existing tendencies in climate changes proposed by the authors is based on the
available facts. Earlier, cyclic behaviour of the world’s river flows was discovered, which was found
to correlate with the cycles of solar intensity. Similar correlation was revealed by the authors for
global temperature anomalies. Based on the wavelet analysis it became possible to notice a phase
inversion in these processes, which, in the authors’ opinion, could be associated with remagnetisation of the Sun. This, for example, explains the hitherto inexplicable interruption in the
temperature rise during the 1950-70-ies. The authors stress that the processes of global climate
changes are of ambiguous character, being consisted of the natural and the anthropogenic
components.
ASSESSMENT OF THE POLICY OF SUSTAINABLE BIOMASS-BASED HEAT
ENERGY SUPPLY AT THE MUNICIPAL LEVEL
G. Klāvs, I. Kudreņickis
Institute of Physical Energetics,
Aizkraukles iela 21, Rīga, LV-1006, LATVIA
e-mail: energy@edi.lv
M. Krug
Environmental Policy Research Centre, Freie Universität Berlin,
22 Ihnestr., Berlin, D-14195, GERMANY
e-mail: mikrug@t-online.de
In search for an effective way to reduce emissions of greenhouse gases the biomass-based heat
energy supply plays an important role. The article describes the application of general policy
assessment methodology, which includes two analytical components: the policy instruments
analysis and the policy performance analysis, for assessment of biomass-based district heating
systems (DHSs), their establishment and operation in the Latvian municipalities. The main
problems and challenges concerning the prospects of biomass-based DHSs in Latvia are discussed
as well as the results are presented of the ex-post analysis of the municipal energy planning and
management practice at the Tukums municipality, which has relevant experience of DHS
renovation based on the use of wood biomass. The key instruments – institutional, financial,
planning and communicative, and factors of success for the DHS renovation are identified.
APPLICATION OF APPARENT IMPEDANCE METHOD AT VARIABLE SPECIFIC
RESISTANCE OF PHASE CONDUCTOR
J. Survilo
Riga Technical University
Kronvalda blv. 1, LV 1010, Riga, LATVIA
The apparent impedance to single-phase earth fault place is obtained applying the classical
algorithm of distance protection. Thanks to a complex character of this impedance, the expression
for the algorithm decomposes into two equations, allowing two unknowns to be calculated: the
Page 2 of 4
LATVIAN JOURNAL of PHYSICS and
TECHNICAL SCIENCES
reactance to a fault place and the fault resistance, provided the faulty phase voltage and current as
well as ground current or zero sequence current are known. To do this, a special mathematical
procedure called here the apparent impedance method is employed, which implies the use of
specific line parameters. For high voltage two-terminal and radial lines of distribution networks
the iterative procedure could be applied under the condition that the faulty phase voltage is
measured in a distribution network with sufficient precision. Among other specific line
parameters, the inconsistency of specific resistance of the phase conductor deserves special
attention because of its unpredictable nature and wide range of deviations causing inadmissible
errors in distribution networks. To cope with this shortcoming, the temperature of the phase
conductor wire should be known at the moment of fault inception. Otherwise, the single-phase
earth fault current should be increased to the level above the half the line load current.
ENERGY USE AND RELATED RISK MANAGEMENT PROBLEMS IN CEE
COUNTRIES
R. Ney
Silesian High School for Management
Ul. Krasinskiego 2, 40952, Kotowice, POLAND
J. Michna
International Center for Energy and Environmental Policy,
3 Wilhelmstrasse D-69181 Leimen, GERMANY
J. Ekmanis, N. Zeltins, V. Zebergs
Institute of Physical Energetics,
21 Aizkraukles Str., Riga, LV-1006, LATVIA
Nowadays, the efficiency of energy use in the Central and East-European (CEE) countries is
insufficient, being much lower than in the “Old Europe”. The problem becomes increasingly
pressing due to non-stop increasing prices of energy carriers (especially of crude oil). The authors
trace the development of research activities in this sphere, classifying the revealed changes in
parameters of energy consumption processes in particular time intervals into deterministic,
probabilistic, and fuzzy. The paper presents a thorough analysis of decision-making in the energy
management at its different levels – normative, strategic, and operative. Particular attention is
given to the management under uncertainty conditions – i.e. to the risk management. The most
wanted research directions in this area proposed by the energy and environment policy (EEP)
Center specially created for CEE countries concern management under risk connected with
innovations, international activities, loss of reputation, etc.. The authors consider in detail the risk
management with insufficient knowledge (non-knowledge) and under chaos. Much consideration
is given to the scenario management and the game theory principles as related to the sphere of
energy use.
A METHOD FOR SELECTION OF SWITCHGEAR TYPE FOR TRANSMISSION
NETWORKS
Z. Krišāns, I. Oļeiņikova, A. Mutule, A. Kalpiņa
Institute of Physical Energetics,
Aizkraukles ielā 21, Rīga, LV-1006, LATVIJA
Since the switchgears of transmission network are for the most part out of date and now such
worn equipment cannot function properly, the issue of selection among switchgear types to be
used in the Latvian power system is very urgent.
Page 3 of 4
LATVIAN JOURNAL of PHYSICS and
TECHNICAL SCIENCES
The method proposed in this article allows selection of switchgear type based on technical,
economic and power supply reliability criteria, taking into consideration operating variables of the
transmission and generation system and its development visions.
The primary criterion for switchgear selection is reliability. For estimation of the switchgear
reliability factor four types of critical faults are to be taken into account: 1) disconnection of one
line, 2) disconnection of one section, 3) 50% disconnection of sections, and 4) 100% disconnection
of sections.
For all types of faults the probability of operational availability and interruption time should be
calculated. To provide calculation of the reliability criterion for several types of switchgears an
original algorithm has been worked out, which is based on disintegration of the calculation
elements of a switchgear type’s configurations. The probability of operational incapability for all
the elements can be calculated by the proposed unified method, which is designed/ conceived as a
module of pilot equipment LDM-PG’08 (in the framework of “Information technology for
sustainable development management of electric transmission networks and generation
systems”). Apart from calculation of operational reliability and interruption time for all types of
faults, the amount of non-supplied electricity and the costs of non-delivery can also be calculated.
ABNORMAL INFLUENCE OF IONS ON SHOCK-INDUCED POLARIZATION IN
BINARY ELECTROLYTES
B. Martuzans, Yu. Skryl
Institute of Mathematics and Computer Science, University of Latvia,
29 Rainis Blvd., Rīga, LV-1459, LATVIA
The study is aimed at modeling the shock-induced polarization of liquid superdiluted binary (KF)
electrolytes at low (<10–4 mole fraction) concentration of K+ and F- ions (i.e. not making direct
contribution to the polarization current). It is supposed that at such a small concentration of
electrolyte only the dipole polarization of water occurs, while the indirect influence of ions is
expressed in its reduced conductivity in the compressed region at increasing concentration of the
dissolved ions. In the authors’ opinion, this influence is connected with suppression of the
transition of water into high-conductivity phase by the ions of electrolyte.
a
b
c
a
b
c
Page 4 of 4