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ISSN 00406015, Thermal Engineering, 2011, Vol. 58, No. 8, pp. 623–628. © Pleiades Publishing, Inc., 2011.
Original Russian Text © K.E. Aronson, Yu.M. Brodov, P.N. Plotnikov, A.Yu. Ryabchikov, B.E. Murmanskii, M.A. Nirenshtein, 2011, published in Teploenergetika.
623
At present, one of the main challenges the operat
ing personnel of thermal power stations (TPSs) have to
cope with is to ensure reliable operation of ageing
power equipment or equipment that has already
worked out its design service life. The complexity of
the problem lies in the fact that the management of
power companies encounters difficulties in finding a
tradeoff between the technical advisability of carrying
out repairs and economic possibility of investing con
siderable sums of money in the repair (restoration) of
both main and auxiliary equipment that has worked
out its depreciation period. At the same time, accord
ing to the data of the Russian Ministry of Energy, 59%
of the main powergenerating equipment has already
been in operation for more than 30 years [1].
One of the promising solutions to this problem is
making a shift to the strategy of repairing power equip
ment according to its actual technical state. This strat
egy must be based on a welldeveloped system of diag
nostics and monitoring of the state of equipment and
on unbiased estimates of its performance indicators [2,
3]. However, the modern monitoring systems, which
are mandatorily installed in newly commissioned
power units, do not find wide use in installations that
have already been in operation for a long time due to
objective and subjective reasons. For solving the acute
problem of ensuring reliable operation of ageing
equipment, the operating and maintenance service for
such equipment at TPSs are presently organized based
on the concept of “life between repairs” [4].
This paper presents an analysis of indicators char
acterizing the reliability of auxiliary equipment that
was carried out by the authors using the results of their
own studies, as well as the results obtained by other
researchers, taking as an example the heattransfer
equipment of steam turbine units, pump sets, and
valves used in process subsystems of power units.
The specific features relating to operating and
maintenance service of auxiliary equipment used in
the process subsystems of a TPS power unit under the
presentday conditions are usually stemming from the
fact that the management of power companies follows
the lastofall principle in earmarking financial sup
port for this equipment. Since diagnostic systems for
auxiliary equipment have been developed and used
insufficiently (to an extent much lower than that for
main equipment), matters concerned with ensuring its
reliability and substantiating costs for repairs and res
toration are becoming a very intricate problem for the
operating personnel and call for a special approach for
settling them. In our opinion, methods of a “critical
link” determined on the basis of peer reviews, as well
as statistical methods for analyzing the damageability
(failures) of auxiliary equipment [5–8] may become
effective in this situation (a system of determining the
“critical link” on the basis of peer reviews has been put
in use at the Perm district power station). Use of the
“critical link” method makes it possible to cut costs for
repairing the auxiliary equipment through ranking this
equipment according to its state (the need to repair it)
taking into account a comprehensive assessment of
reliability and possible financial losses that are likely to
occur if this equipment of the power unit fails. The use
of statistical methods makes it possible to analyze fail
ures of a large number of elements of a similar type,
estimate their reliability indicators, and thus substan
tiate costs for repairing auxiliary equipment.
The Firm ORGRES carried out a statistical analy
sis of the reliability of power equipment used at TPSs
on the basis of drawn up failure reports in the country’s
Unified Energy System since the mid1970s to 2000
[9, 10]. A generalization of these data in the form of
failure distribution (%) by different kinds of power
An Analysis of Indicators Characterizing the Reliability
of Auxiliary Equipment of Power Units
K. E. Aronson, Yu. M. Brodov, P. N. Plotnikov, A. Yu. Ryabchikov,
B. E. Murmanskii, and M. A. Nirenshtein
Ural Federal University, ul. Mira 19, Yekaterinburg, 620002 Russia
Abstract
—We consider indicators characterizing the reliability of power station auxiliary equipment obtained
by processing the results from routine and special tests, various studies, replies to questionnaires given to spe
cialists of thermal power stations, official statistical data on the damageability of thermal power station equip
ment, and studies of repair documentation. We also present procedures for processing, analysis, and general
ization of obtained information.
DOI:
10.1134/S0040601511080039
624
THERMAL ENGINEERING Vol. 58 No. 8 2011
ARONSON
et al.
unit equipment for the period from 1984 to 2000 is
given below.
It can be seen that the main equipment tradition
ally accounts for the largest number of failures; how
ever, a significant part of failures relates also to the
auxiliary equipment of steam turbine units and valves.
For TPSs with transverse links, the quantities of
failures (%) caused turbine shutdowns (critical fail
ures) with respect to the total number of failures of this
auxiliary equipment are as follows:
A considerable (more than 80%) fraction of critical
failures of condensers, ejectors, and valves is quite
striking. Failure reports, which served as the basis for
[9, 10], usually record failures of equipment items
causing turbine shutdowns or a considerable reduction
of TPS power output. In our opinion, the turbine fail
ure reports do not reflect a considerable part of auxil
iary equipment failures that were revealed during
operation and reflected in operative repair logs. If
these failures are taken into account, the fraction of
critical failures becomes smaller.
As was shown in [6–8, 11], the use of internal
information available at TPSs makes it possible to
monitor the technical state of steam turbine auxiliary
equipment, as well as to formulate and solve statistical
problems, which, in turn, makes it possible also to
shape a quantitative assessment of its reliability indica
tors. Statistical methods are used due to the fact that
process circuits of power units contain a large number
of similar elements, such as valves and tubes in heat
transfer equipment (e.g., a 300MW power unit com
prises more than 1300 valves, and the condenser of this
turbine contains 19592 tubes).
The experience the authors of this paper have
gained for more than 30 years of their research work at
different TPSs makes it possible to formulate the main
objectives to be pursued by an analysis of reliability
Boiler 40.2
Auxiliary boiler equipment 2.1
Turbine 1 6 . 0
Auxiliary turbine equipment 8.6
Electrical equipment 22.9
Pipelines 2.1
Valves 8.1
Condenser 96.1
Electrically driven feedwater pump 34.6
Highpressure heaters 1.5
Lowpressure heaters 1.9
Ejector 96.7
Circulation pump 34.2
Valves 83. 2
indicators, which consist, as applied to shellandtube
heattransfer equipment, in substantiating the periods
of time after which the apparatuses (tube systems)
must be replaced, revealing typical factors due to
which tubes suffer damage before the apparatuses
work out their service life, and scheduling the scopes
in which repair and restorative works must be carried
out.
The state of a heattransfer apparatus’ tube system
serves most frequently as a criterion for determining its
limiting state and, hence, its service life. The standard
service life of heattransfer apparatuses is equal to
30 years [12]. However, the real service life of an appa
ratus may vary considerably depending on its type and
its location in the steam turbine unit process circuit,
and it is recommended that the replacement of the
tube systems of heattransfer apparatuses be timed to
the turbine (power unit) overhauls [4].
The analysis and generalization of data obtained by
the authors of this paper and ORGRES specialists
regarding the periods of time after which tube systems
and entire apparatuses are replaced show on the whole
that these periods of time differ considerably for dif
ferent TPSs (by a factor of 2 or more: from 8–15 to
30 years) [7, 11]. This is attributed to nonidentical
conditions under which the apparatuses operate, to
changes made in their design (primarily in the use of
materials), to the quality of manufacturing the appara
tuses, and to the chemical composition of coolants.
The peculiarities of figures characterizing the damagea
bility of heattransfer apparatuses pointed out in [7, 11]
testify that their service life cannot be taken as a standard
ized indicator of reliability in view of its ambiguity.
The maximal admissible fraction of blanked off
tubes is another criterion the operating personnel of
TPSs uses for substantiating the time at which the tube
systems of heattransfer apparatuses must be replaced
[11]. This indicator should be considered in the fol
lowing two aspects:
—the economic aspect (the dates at which the tube
systems of heattransfer apparatuses have to be
replaced are substantiated by determining the moment
of time when the losses due to operation of the appa
ratus with a reduced heattransfer surface become
equal to the costs for replacing the tube system taking
into account the operating costs during the year cov
ered by calculations for a new apparatus [7]); and
—the operating aspect (the uniformity of the lay
out of blanked off tubes over the tube bundle cross sec
tion is analyzed, and the rate with which tubes were
blanked off is taken into account).
The results obtained from calculations of the frac
tion of damaged heattransfer surface at which
replacement of the entire tube system is economically
advisable are given in the table. The ranges of the
obtained values are due to different (within 20%) costs
of fuel. These data, which represent the maximal esti
mates, should be corrected taking the operational
THERMAL ENGINEERING Vol. 58 No. 8 2011
AN ANALYSIS OF INDICATORS CHARACTERIZING THE RELIABILITY 625
constraints into account. Thus, if failed tubes concen
trate in one zone (the water pass) of an apparatus, this
results in the need to decrease the permissible number
of failed tubes for the apparatus as a whole. This also
results in an increased pressure drop across the appa
ratus: the bundle tubes remained in operation carry
water flow with a higher velocity, which may lead to a
higher rate of corrosion–erosion wear and more
intense failures of these tubes. The operating manuals
for the horizontal deliverywater heaters produced by
the Ural Turbine Engine Works (UTMZ) impose lim
itations on the maximal number of adjacent blanked
off tubes, which must not be more than six. In the
opinion of UTMZ specialists, this is determined by
the reliability of the rolled connections of healthy
tubes situated in the given zone of a tube bundle. Thus,
if the blanked off tubes lie in one zone of a tube bundle,
it is necessary to reveal and remove the factors causing
this damage and replace the failed tubes as far as pos
sible.
As is well known, the tubes of heattransfer appara
tuses fail at different rates in different periods of their
operation [13]. The initial period (runningin) is char
acterized by a high failure rate (faulty tubes are
rejected after replacement of the apparatus tube sys
tem). This period is usually rather short and ends with
hydraulic pressurization of the heattransfer appara
tus. During normal operation, which corresponds to
the apparatus service life, the failure rate is relatively
low. A dramatic increase in failure rate is used as a sign
that the time of finishing the operation or replacing
(overhauling) an apparatus is attained. The studies [6–
8] carried out by the authors with the use of statistical
methods made it possible to propose the parameter of
tube failure rate as a new indicator characterizing the
reliability of condensers determining the period of
normal operation and, accordingly, the time at which
the tube system must be replaced. The failure rate of
apparatus tubes is calculated from the formula
(1)
where
Δ
n
fail
is the number of tubes blanked off in the
period from the previous to the current repair of the
apparatus,
N
is the total number of tubes in the appa
ratus,
n
fail
is the total number of tubes blanked off in
the apparatus from the commencement of its opera
tion to the previous repair, and
Δ
T
is the time for
which the apparatus has been in operation since the
previous repair [13, 14].
Tubes of an apparatus may fail due to different fac
tors. Erosion–corrosion wear in the course of opera
tion for a sufficiently long period of time is one of the
main factors causing their failures (44.6%). Damage to
the outer surface is inflicted as a result of droplet
impingement erosion, and erosion of their inner sur
face occurs due to poor quality of circulating water
carrying suspended matter (which sometimes consist
λΔnfail
Nn
fail
–()ΔT
,=
of quite a large amount of abrasive particles, the effect
of which leads to degradation of the inner surface of
tubes, especially in the zone of their inlet parts, the
length of which is approximately equal to the thickness
of tube sheets). Corrosion failures of condenser tubes
occur as a consequence of inconsistency between the
material of tubes and chemical composition of cooling
water, which gives rise to different kinds of corrosion
(general corrosion, loss of zinc in brass, etc.). Failures
due to loss of tightness in tubes and their rolled con
nections with tube sheets are next in significance
(39.3%). Loss of tightness in apparatuses occurs both
due to corrosion wear of tubes (decreasing the thick
ness of their walls in the areas of rolled connections)
and due to their friction wear in the zone where the
tubes pass through the holes in intermediate partitions
(vibration of tubes is the main factor causing such wear).
Vibration may also lead to degraded tightness of rolled
connections between tubes and tube sheets and finally to
complete loss of their tightness [5].
To decrease the influence of rare random factors
(damage inflicted to tubes by elements used in the flow
path of turbines’ lowpressure cylinders and errors
committed by the personnel), it is recommended to
determine the rate of failures (damages) calculated
from (1) as an integral mean value characterizing the
time for which an apparatus has been in operation:
(2)
where the subscript
i
corresponds to different operat
ing times of an apparatus between repairs during nor
mal operation.
According to our estimates, the value of
λ
m
for the
period of normal operation of turbine condensers
must not exceed 0.2
×
10
–6
h
–1
. The calculation car
ried out according to expression (2) makes it possible
to take into account the effect the nonuniformity of
the damage accumulation process has on the esti
mated value of the mean indicator characterizing the
failure rate of tubes.
In [6–8], an approach for determining the indica
tors influencing the effectiveness of repair service car
ried out for heattransfer apparatuses, in particular, a
highpressure heater (HPH), was proposed, which has
been implemented for the first time at the Surgut
λm
ΣλiΔTi
ΣΔTi
,=
Fraction (%) of damaged heattransfer surface area of appara
tuses at which replacement of their tube systems is advisable
Turbine Condenser HDWH LPH1 LPH4
T110/12012.8 20–25 8–10 11–15 5–6
T250/30023.5 12–16 14–17 17–20 4–6
K30023.5 7–10 – 5–7 5–7
Note: LPH is a lowpressure heater, and HDWH is a horizontal
deliverywater heater.
626
THERMAL ENGINEERING Vol. 58 No. 8 2011
ARONSON
et al.
GRES1 district power station. The repair documen
tation available at this power station was processed, the
results of which were used to obtain statistical density
distribution functions for the time to restore the HPH
and time of HPH operation between repairs. The sys
tem of equations for the change of HPH states (ser
viceable state–scheduled repair–emergency repair)
was solved, from which it became possible to quantita
tively estimate the guaranteed term of repair service
for HPH at district power stations, which was found to
be 70 days. Such duration of the guaranteed period is
because the HPH has poor maintainability, which just
results in high (up to 4%) probability that the appara
tus is repaired with poor quality. An analysis shows that
the probability of HPH failure after the recommended
guaranteed period decreases and the probability of
HPH failurefree operation to the next scheduled
diagnostic service increases.
The failures of pumps (circulation, condensate,
and electrically and turbinedriven feedwater pumps),
which as a rule led to shutdowns of turbines (power
units), were also analyzed. Data on more than 150
steam turbine units of different types with capacities
from 12 to 800 MW installed at 60 TPSs collected for
the period from 1994 to early 1999 were used in that
analysis. Failure reports (drawn up at TPSs), question
naires (compiled according to the peer review
method), information from power systems, etc.,
served as sources of information. In addition, the
repair documentation available at power stations was
used to analyze the flaws revealed in pumps during the
period of their repairs. This information is necessary
for developing systems intended for monitoring the
technical state and diagnosing the equipment of steam
turbine units.
An analysis of flaws occurring in pumps showed
that failures of bearings occurred most frequently in
circulation pumps (in 54.2% of cases) and in conden
sate pumps (up to 40%). Failures of the flow path,
including those caused by ingress of foreign subjects
were noted mainly in feedwater pumps (39.4%); for
other pumps, this kind of failures accounts for 11–
17% of their total quantity. Damages inflicted to valves
and pipelines accounted for 9–20% of failures in all
pumps except circulation pumps, in which these dam
ages almost do not occur at all.
One of the objectives pursued by an analysis of
indicators characterizing the reliability of valves con
sists in determining typical flaws in different types of
valves operating in various process subsystems of
power units at TPSs and in scheduling repair and
restorative measures for valves.
The analysis of reports on failures of power units at
Russian TPSs occurred for 20 years (from 1980 to
2000) that was carried out in [10] showed that typical
flaws of valves depend on their types (designs), loca
tion, and conditions of their operation and mainte
nance service. Thus, 30–70% of flaws occurring in
valves and gate valves are connected with leakage of
medium through the stem gland and with damage of
shutter and stem parts. The main flaws (up to 78%) in
safety valves occur as a result of damages in the shutter
and stem, and flaws in check valves occur mainly due
to the wear of shell parts and leakage of medium
through the shell seals. For check valves and cutoff
valves, defects of their design and manufacture are a
factor accounting for an essential (30–45%) part of
their failures. Shortcomings of operation and repairs
are pointed out in reports as the main factors (up to
70% or more) causing failures of different valves.
To perform a detailed analysis of the damageability
of valves, the authors carried out a special study (based
on repair documentation for 5–17 years and peer
reviews carried out by operating personnel) for 19
power units designed for supercritical parameters of
steam with capacities 300–800 MW installed at the
Reftinskii, Srendeuralsk, and Surgut GRES2 district
power stations. The analysis was carried out with
respect to certain process systems of power units (live
steam, main condensate, feedwater, starting system,
reheating, and others) taken separately unlike the
approach used in [10], which is due to the specific fea
tures of thermophysical processes (parameters of heat
carriers) in each of them. We determined the specific
(per valve in a subsystem) number of valve repairs a
year:
n
r
=
N
r
/
N
v
,
where
N
r
is the number of valve repairs a year in a pro
cess subsystem, and
N
v
is the number of valve units in
the subsystem.
With the estimated specific indicator used in the
analysis, it became possible to avoid the need to take
into account the total number of valves in the process
systems of different power units.
The values of the indicator
n
r
of a concrete process
subsystem for each power unit were united for the ana
lyzed periods of time for all power units into a unified
set, after which the correctness of such uniting was
checked according to Mann–Whitney’s criterion
[13]. The performed analysis showed that the data on
n
r
for each process system and for almost all the con
sidered power units form statistically uniform sets.
Figure 1 shows how the values of the mean indicator
n
r
are distributed for different process systems of power
units. The largest number of repairs falls on the valves
used in the subsystems of steam reheating, safety
valves, and boiler starting unit, and their smallest
number falls on the valves used in the main condensate
and feedwater subsystems.
Figure 2 shows the distribution of the indicator
n
rep
=
N
rep
/
N
r
, which characterizes the ratio of the
total number of valve replacements
N
rep
to the total
number of valve repairs
N
r
. The value of
n
rep
increases
with increasing the capacity of power units. In our
opinion, this is attributed to the fact that, as the power
THERMAL ENGINEERING Vol. 58 No. 8 2011
AN ANALYSIS OF INDICATORS CHARACTERIZING THE RELIABILITY 627
unit capacity increases, so do the sizes of valves (nom
inal bore) and laboriousness of their repairs (it is more
advisable to carry out their repairs at specialized enter
prises).
An analysis of correlation between the volumes of
valve repairs and duration of power unit repairs
showed that this correlation is inessential; hence, the
volumes of valve repairs do not depend on the kind of
power unit repair (overhaul, medium repair, or current
repair).
It was determined that special reliability indicators
individual for each type of power unit auxiliary equip
ment need to be developed. The integrated reliability
indicators adopted for estimating the state of boilers
and turbines are used for making the optimal manage
rial decisions on planning the technical use of main
equipment, making it more efficient, and manufactur
ing and procuring spare parts [15, 16]. As a rule, aux
iliary equipment is repaired in the same period of time
for which the main equipment of a TPS is taken for
repairs. Therefore, one of the objectives pursued by an
analysis of indicators characterizing the reliability of
auxiliary equipment must consist in substantiating the
time of equipment repairs (replacement) and scope in
which it should be carried out based on the results
obtained from diagnostics and monitoring of the tech
nical state, and from an analysis on revealing the typi
cal factors causing failures of the given equipment.
Thus, the facts presented above testify that there is
a pressing need to continue (resume) activities for col
lecting and analyzing information on failures and cal
culating the indicators characterizing the reliability of
power equipment at TPSs, which must be carried out
at the level of the Ministry of Russia for Energy. Work
should also be carried out on extending the system of
indicators characterizing the reliability of different
kinds of power equipment. These reliability indicators
can be tailored to the operating conditions at concrete
TPSs on the basis of information systems used at
TPSs, equipment databases, and electronic logs of
flaws. By using the reliability indicators obtained in
this way it will be possible to organize operational and
repair service of power equipment in a more efficient
manner and correctly distribute financial funds for
repairing and restoring the equipment.
Systems for monitoring and diagnosing the techni
cal state of power equipment form the basis for esti
mating the reliability indicators of this equipment.
Development of these systems is the necessary (and in
some cases mandatory) stage in making a shift at
power companies to the strategy of repairing power
equipment according to its actual technical state. The
fundamental principles of a comprehensive system for
monitoring the technical state of power equipment
have already been developed [17], and individual com
ponents of the system have already been implemented
[8, 11, 18] at some TPSs.
Financial support for repairs and maintenance of
auxiliary equipment is usually provided according to
the “lastofall” principle, and methods for estimating
the state and reliability indicators of this equipment
need to be developed for substantiating the time and
scopes in which these repairs and maintenance activi
ties must be carried out. The use of an individual
approach and statistical methods for solving these
tasks makes it possible to obtain quantitative estimates
of the specific indicators characterizing the reliability
of auxiliary equipment and develop efficient systems
for diagnosing and monitoring its technical state on
the basis of these estimates.
REFERENCES
1. A. N. Shishkin,
State Policy Regarding the Commission
ing and Decommissioning of Power Capacities: Problems,
Ways of Solving Them, and Control
, http://minenergo.
gov.ru/upload/iblisk/a64/4c94bdeddb2149fbd71781bl
e3adccbl.pdf.
2.
A Concept for Improving the Strategy of Maintenance and
Repair of Power Units at Thermal Power Stations
(AO
TsKB Energoremont, Moscow, 1996) [in Russian].
3. A. V. Andryushin and E. Yu. Shnyrov, “Using a Project
Management Philosophy to Develop a System for
Organizing Repairs to Power Equipment,” Teploener
getika, No. 10, 17–21 (2004) [Therm. Eng., No. 10
(2004)].
4.
SO (Enterprise Standard) 34.04.1812003: Rules for
Organizing Maintenance and Repairs of Equipment Used
n
r
0.4
0.2
0
12345678
Fig. 1.
Specific quantities of valve repairs in the process
systems of 300–800MW power units. (
1
) Live steam, (
2
)
reheating, (
3
) injections, (
4
) safety valves, (
5
) main con
densate, (
6
) feedwater, (
7
) boiler feed unit, and (
8
) boiler
starting unit.
n
rep
0.2
0.1
0
1234
Fig. 2.
Ratio of the number of valve replacements to the
total number of valve repairs for power units equipped with
300–800MW turbines. (
1
) K300 (produced by the
Kharkov Turbine Works [KhTZ]), (
2
) K300 (produced by
the Leningrad Metal Works [LMZ]), (
3
) K500 of KhTZ,
and (
4
) K800 turbine of LMZ.
628
THERMAL ENGINEERING Vol. 58 No. 8 2011
ARONSON
et al.
in Buildings and Structures of Power Stations and Electric
Networks
(RAO UES of Russia, Moscow, 2004) [in
Russian].
5. P. N. Plotnikov, Yu. M. Brodov, and B. E. Murmanskii,
“A Comprehensive Analysis of the Reliability Indica
tors of Heat Exchangers of Steam Turbine Units,” Tep
loenergetika, No. 2, 45–48 (2007) [Therm. Eng. No. 2
(2007)].
6. K. E. Aronson, Yu. M. Brodov, A. Yu. Ryabchikov, and
B. E. Murmanskii, “Statistical Simulation of Failures
of Heat Exchanger in Developing a Comprehensive
System for Monitoring the State of SteamTurbine
Units,” Teploenergetika, No. 8, 71–77 (2007) [Therm.
Eng., No. 8 (2007)].
7. Yu. M. Brodov, K. E. Aronson, A. Yu. Ryabchikov, and
B. E. Murmanskii, “Estimating the State and Predict
ing the Remaining Service Life of Heat Exchangers
Used in Steam Turbine Units,” Nadezhn. Bezop.
Energ., No. 3 (6), 12–18 (2009).
8. K. E. Aronson, A. Yu. Ryabchikov, Yu. M. Brodov, and
B. E. Murmanskii, “A Procedure for Estimating the
Condition of the Tube Systems of Steam Turbine Con
densers and Predicting Their Remaining Service Life,”
Elektr. Stn., No. 2, 25–31 (2010).
9.
An Overview of Faults Occurred in the Main Kinds of
Equipment Used at Power Stations with Transverse Links
and in Heat Networks
(ORGRES, Moscow, 1974) [in
Russian].
10.
An Analysis of the Operation of 150–1200 MW Power
Units for the Period 1980–2000
(SPO ORGRES, Mos
cow, 2002) [in Russian].
11. Yu. M. Brodov, K. E. Aronson, A. T. Mutovin, et al.,
“Improving the Efficiency and Reliability of Steam
Turbine Units under Field Conditions,” (UrFU, Yeka
terinburg, 2010) [in Russian].
12.
OST (Industry Standard) 108.005.1582: The Sectoral
System of Managing the Quality of Production in Manu
facturing PowerGenerating Machinery and Equipment.
Estimating the Quality Level of Power HeatTransfer
Equipment at Power Stations
(NPO TsKTI, Leningrad,
1983) [in Russian].
13. V. V. Bolotin,
Predicting the Service Life of Machines and
Constructions
(Mashinostroenie, Moscow, 1984) [in
Russian].
14. R. P. Runlon,
A Handbook on Nonparametric Statistics
(Finansy i Statistika, Moscow, 1982) [in Russian].
15. A. A. Rimov, “The Current State of Sectoral Statistics
on the Reliability and Technical Use of Equipment,”
Elektr. Stn., No. 12, 2–5 (2009).
16. A. A. Rimov, “Methodical Aspects of Estimating the
Reliability and Technical Use of Thermal Power Equip
ment at Thermal Power Stations,” No. 3, 9–14 (2010).
17. K. E. Aronson, N. N. Akif’eva, Yu. M. Brodov, et al.,
“The Concept of a Comprehensive System for Moni
toring the State of the Equipment of a Power Unit,”
Teploenergetika, No. 2, 47–53 (2002) [Therm. Eng.,
No. 2 (2002)].
18. K. E. Aronson, V. I. Bezgin, Yu. M. Brodov, et al.,
“A System for Providing Information Support to Mak
ing Managerial Decisions Concerned with Mainte
nance of Equipment at Thermal Power Stations,” Elektr.
Stn., No. 10, 55–61.