Table Of ContentAPAP2009, October 18~21, 2009 Jeju, Korea
1
Identical Approach to BtB Control Scrutiny in
Large Power Grids
A. Grobovoy, Member, IEEE, A. Arestova, Member, IEEE, Y. Sidorkin
construction of 750 MW ±125 kV Back-to-Back (BtB)
Abstract--The paper deals with the results of simulation of converter station at the boundary Chinese in Heihe town has
back-to-back converter stations potential, which can be been achieved. Taking into account the existing boundary
implemented in large power grids and coexist with AC electricity trading between Russia and China, one can assume
transmission lines in the same transmission corridor. Such
that the Russian Far East interconnected power system can be
conditions can be appear in the case of possible UCTE-IPS/UPS
connected with surrounding power systems either by purely
interconnection as well as in the case of coupling of the Russian
Far East Interconnected Power System and Chinese National DC or hybrid ties contained both AC and DC devices. The
Power Grid. In spite of the fact that the paper focuses on China- same concept will be perhaps examined in the frame of the
Russia interconnection the simulation experience could be used new project that has been undertaken by the European
envisaging further development for the UCTE-IPS/UPS power Commission and Russian Federal Agency of Science and
grid. The paper has dealings with possible influence of Heihe
Innovation. The project concerns a possible intelligent control
(China) BtB plant on behavior of the Russian Far East IPS under
and coordination system for UCTE-IPS/UPS interconnection
faults at the 500 kV transmission lines.
including the interconnection technologies based on DC or
Index Terms--Power network model, BtB converter station, hybrid ties.
UCTE-IPS/UPS interconnection, EUROSTAG software. One can assume that UCTE-IPS/UPS interconnection can
be exceptionally realized with the use of the so-called Back-
I. INTRODUCTION to-Back (BtB) converter stations. Fig. 1, borrowed in [1] and
MODERN state of High Voltage Direct Current (HVDC) completed by pictograms of BtB for some possible corridors
technologies based on the state-of-the-art technique of of power transfer, is based on recommendations which have
Voltage Source Converters (VSC) determines general interest been done in the reference regarding possible transmission
of electrical engineers for power network interconnections corridors between UCTE and IPS/UPS power grids. The
with the use of the so-called hybrid transmission systems picture shows only one of several ways when the BtB
which have combined with both AC and DC transmission converter stations shunt some AC transmission ties could be
lines. For instance, several variants for interconnecting the put into operation to form the interconnection.
Russian Far East and Siberian interconnected power systems Taking into account also three possible transmission
have been examined recently in Russia. The above mentioned corridors for interconnection of the Russian Far East
first power system is autonomous while the second one is interconnected power system with surrounding power systems,
working with Russian Power Grid synchronously. So far the one can assume that some control problems can become look
problems of voltage instability are the barrier for synchronous like for UCTE-IPS/UPS and the Russian Far East power
operation of the Russian Far East and Siberian interconnected system coupled with Siberia and China power grids. Thus the
power systems. At the same time there is necessity for common problems inherent in large power systems could be
electricity interchange between these power systems, which resolved with the use of some prototype of network model. In
can become extra-important factor for impending market our opinion, the prototype for impending UCTE-IPS/UPS
conditions. On the other hand, the international conversation interconnections can be the Russian Far East interconnected
between Russian and Chinese sides about electricity foreign system coupled with the surrounding power systems
commerce was finished not long ago. The agreement about The problems which emerge under constructing such hybrid
interconnections can be solved with the use of the special
This work was supported in part by Russian Federal Agency of Scientist simulation tools that can give the grounds for preliminary
and Innovations under the Government Contract 02.527.11.0004. discussions of the interconnection emergency control
A. Grobovoy is with Power System Emergency Control Laboratory, PO principles. As common tools for these aims the EUROSTAG
Box 49, Novosibirsk 630064 Russia (e-mail: [email protected]).
software has been assigned [2].
A. Arestova is with Power System Emergency Control Laboratory, PO
Box 49, Novosibirsk 630064 Russia (e-mail: [email protected]). The emergency control strategies for the UCTE-IPS/UPS
Y. Sidorkin is with Novosibirsk State Technical University, 20 Karl Marx will depend on a method of interconnecting that can be
Str, Novosibirsk 630092 Russia (e-mail: [email protected]) realised as asynchronous or synchronous one. Difference
2
To Saha-
Yakut BtB HVDC converter
500 kV transmission line
To
220 kV transmission line
Siberia
Zeya Komsomolsk-
HPP na-Amure
Amurskaya
Khabarovsk
Bureya Khehzir
HPP
Heihe
Shuangyashan Luchegorsk
Qunlin SPP
Suihua
Songbei
Daqing HananYongyuan Mudanjiang
Fangzheng SPP Dalnevostochnaya
To Heixin To Baojia To Linhai Vladivostok
Fig. 1. Possible ways for UCTE – IPC/UPC interconnection with the use of
the DC and AC technologies: gray, brown, and green colors symbolize 750 Fig.2. Sketch power network model for simulation
kV, 400 kV, and 230 kV transmission lines
II. POSSIBLE EMERGENCY CONTROL STRATEGY
between these variants consists in the use of the technologies
of AC or DC for the interconnection. From the point of view
A. Possible way of SPS coordination
of the interconnection emergency control the variant of hybrid
We assume that the structures of the SPS complexes that
interconnection with the use of both AC and DC technologies
will be responsible for UCTE-IPS/UPS interconnection
seems very probable. One of the benefits of the hybrid
stability have to belong to one of the class such as centralized
interconnection consists in the possible BtB converter station
or decentralized one. In that case, there are several strategies
utilisation for damping of low frequency oscillations that can
for development of possible SPS structure for the UCTE-
arise as result of some faults or disturbances both in UCTE
IPS/UPS intersection [6]. One of them is based on assumption
and IPS/UPS power systems.
that each of the participants, the UCTE and the IPS/UPS, is
In this case the potential of the so-called Wide Area
responsible for stability of its own part of the power grid. In
Measurement and Control Systems (WAMS/WACS) can be
that case, the SPS initiated by a local detection system have to
used for the BtB active power modulation very efficiently.
separate the UCTE power systems from the IPS/UPS in the
However, from considerations of the obstacles conditioned by
time of all possible disturbances.
some problems with the detailed power network models as
This way doesn’t seem to be the best variant of the UCTE-
well as the reduced model, the simulation of UCTE-IPS/UPS
IPS/UPS operation. In the conditions when the interface of
behaviour is delaying. In these conditions, in order to not
UCTE-IPS/UPS can be formed on the base both of VSC-
waste time, we decide to use the well known power network
HVDC and AC transmission ties, only AC transmission line
model of the Russian Far East Interconnected Power System
can be opened. However, this method intends certain
[3-4] in couple with Chinese North-East Power Grid whose
coordination of different SPS complexes. Fig. 3, borrowed in
approximate model has been discovered in [5]. Fig. 2 shows
[7], offers two possible SPS strategies which assume that the
the sketch power network model of the Russian Far East
objective of the centralized SPS complexes is to maintain
Interconnected Power in couple with Chinese North-East
electricity change in UCTE-IPS/UPS market in all possible
Power Grid.
emergency situations. In that case, the centralized SPS
One more reason for such approach is absence of the
complexes or remote (local) SPS devices can be situated on
adequate model of UCTE-IPS/UPS because of great number
one side of the intersection but its influence has to be applied
of various barriers while the model of the Russian Far East
to another side.
and Siberian interconnected power systems is well known. It
The centralized SPS systems have to be used in order to
is clear that one day the problem of the emergency control
correct the set points of remote SPS devices. The set points
coordination for the Russian Far East interconnected power
have to be transferred with the use of telecommunications
system and China State Power Grid will make one's
means. Another way of coordination consists in transferring to
appearance. In this connection, combined efforts of Russian,
the centralized SPS complexes the information regarding
European and Chinese experts could be appropriately. It
power system network models for correcting control actions
seems that possible results of European-Russia project can suit
by the centralized SPS complexes without assistance.
for China-Russia impending cooperation and vice versa.
3
Fig. 3. Two possible strategies for SPS coordination in UCTE-IPS/UPS interconnection
In that case, both power network model and the decision systems for realization of coordinated defence plans against
tables can be used for forming control actions. Fig. 3 explains large disturbances in power systems, and so on.
the possible SPS structure for the UCTE-UPS/IPS One can understand that accuracy or inaccuracy of any
interconnection project. It is needed to note that the information about parameters of power networks as well as
coordination centres shown in Fig. 3 could be located in other the parameters of generators and their controls does not
places, for example, at the Ukraine and Switzerland. It should cardinally influence on the conclusion of this investigation. In
be the subject of WAMS/WACS structures designing in the fact, the main purpose of the examination is to compare only
near future. The positions of the centralized and the two possible variants for interconnection of large power grids
coordinating SPS systems on the map have been chosen to give the basis for the subject discussion of possible
roughly. Its accurate location has to be determined after detail technologies of UCTE-IPS/UPS interconnection. In the same
study and attainment of agreement on the principles of way one may think about the power network conditions which
emergency control for the UCTE-IPS/UPS interconnection. were assigned for the investigation. Actually, there are plenty
The positions of the centralized SPS complexes are of schemes and regimes in the power grids. However, the
suggested taking into account the existing and possible power examination of these situations oversteps the limits of the
transfer corridors that will be formed by the 750 kV given study.
transmission lines. The bidirectional white arrows with orange In accordance with this conception at last two control
color border mean the transfer of special information contents centres have to be provided at UCTE and IPS/UPS
which depend on the principle of the centralized SPS correspondingly. Each of the centres should place at another
complexes - behaviour prediction or behaviour-assumption. control centre’s disposal the information about actual state of
Two directions of the arrows have to emphasize an ability of its power network model. The information has to be enough to
the centralized SPS complexes to fulfil the power system execute simulations which needed for UCTE-IPS/UPS
Dynamic Security Assessment (DSA) and to transfer the interconnection dynamic security assessment. Next, one of the
information in the coordinating SPS system. The white arrow control centres send to the system protection schemes (SPS)
with blue color borders means the transfer of the information complexes, which will responsible for keeping of UCTE-
required for DSA for the UCTE-IPS/UPS power grid at the IPS/UPS interconnection stability, one of two kinds of
UCTE TSO and the IPS/UPS TSO separately. The black information: 1) the full or an approximate equivalent of
arrows symbolize the transfer of set points for the remote SPS UCTE-IPS/UPS power network, which is needed for power
devices. Four small arrows originated from the brown system simulations that have to be executed at the SPS
rectangles symbolizing the SPS complexes and SPS devices complexes, 2) the calculated setting of control actions, which
(remote and local) mean the local telemetry and tele-indication will be used for correction of the current control actions.
system for collection of information, and also the system for Possibility of SPS and BtB coupling shown in Fig. 2. The
transferring WADS and control signals. Lastly, the similar first BtB converter station was modeled by the traditional BtB
arrows originated from the black and red rectangles (the model. The second one was represented by the constant load.
UCTE TSO and the IPS/UPS TSO) symbolize the all The rated power of the first BtB converter station is 200 MW
communication tools including WAMS and some satellite while its operation power is 150 MW.
4
The present-day the ideas regarding emergency control by the traditional BtB model. The second one was represented
strategies in large power system are based, in the main, on the by the constant load. The rated power of the first BtB
centralized emergency control principles. However, converter station is 200 MW while its operation power is 150
unexampled propagation of WAMS/WACS technologies MW.
gives us a strong conviction about implementation of The new 500 kV “Suihua - Heihe BtB” transmission line
decentralized principle in the near future. Just at the right time was constructed by Chinese side in order to connect North-
the above mentioned ICOEUR project will deal with BtB and
East Power Grid with the Russian Far East Interconnected
WAMS/WACS technologies. In the frame of the project the
power system. The parameters of the transmission line have
decentralized conception could be adapted to a new strategy
been determined with the use of the typical linear parameters
of UCTE-IPS/UPS interconnection.
for 500 KV transmission lines and rough estimate of the
Really, BtB converter stations are enough complicated.
transmission line length with the use of the Google Earth
This circumstance demands the high degree of automation.
software. The same approach has been applied to determine
One can assume that the plants for UCTE-IPS/UPS
the parameters for other Chinese 500 kV transmission lines.
interconnection can be placed near to SPS complexes which
Due to the absence of any authentic information about
will responsible for UCTE-IPS/UPS interconnection stability.
lengths of 220 kV transmission lines, shunting the 500 kV
The point is that, in the modern conditions, when we are
talking about BtB VSC technologies, as well as about “Suihua-Heihe BtB” one, the location of the load buses have
WAMS/WACS ones, the local SPS centres can be combined been determined by dividing of the 500 kV transmission line
with BtB because of several reasons for that. For instance, length onto five equal segments. The loads at the buses have
possible modulation of BtB active power provides a good been selected so that power flow in the power network 500-
chance to decrement the low frequency oscillations with the 220 kV corresponded to the power flow shown in [5]. The rest
use of WAMS/WACS tools. Effective ways for keeping of part of Chinese North-East power network was represented by
voltage stability can be suggested by BtB SVC plants. At last, four equivalent generators in Quinlin, Daqing, Fangzhen,
from the point of view of optimal power flow in the market Heixin as well as the 500 kV transmission lines shown in
environment, new effective technologies for power network Fig. 2. The generators were represented by synchronous
conditions could be realized with the use of BtBs. machine models with their automatics such as the governors
and automatic voltage regulators with power system
III. NETWORK MODEL USED FOR SIMULATION stabilizers.
A. Power network model
IV. SIMULATION RESULTS
The simulated power network is based on the
configuration of the 2008 Russian Far East interconnected A. BtB constant power model
power system. The Bureya Hydro Power Plant (HPP) was
It is assumed that the BtB converter station can instantly
represented by six generation units (6x335 MW). The
vary the power flow according to commands sent from SPS
intersystem tie between Saha-Yakut and the Amur power
complex at the Zeya HPP. The examination was only done for
systems was strengthened by an additional 500 kV
one of numerous possible ratios between the imported power
transmission line. The new 500 kV “Amurskaya - Heihe BtB”
with the use of the BtB converter station power and the
transmission line that is under construction now, was modeled
available one for power system stability emergency control.
of course. For the goals of the given investigation the
The considered case is enough to confirm the principal
consumer loads of the power network were modified to
possibility of such approach. Without question, the use of
guarantee the normative Available Transfer Capacity through
Heihe BtB converter station for minimization of remote load
the some given sections of the transmission system.
shedding value in the Russian Far East power grid could be
The rated power of Heihe BtB converter station is of 750
examined in detail. Common efforts of Chinese and Russian
MW. Two possible configurations of the interstate ties were
engineers are needed to simulate both power network of North
examined: 1) with the use of BtB converter station solely, and
China and the Russian Far East properly. It could be
2) with the use of the BtB converter station shunted by the
wholesome if the given paper will assist Chinese and Russian
220 kV transmission line. In the first case the operating power
experts to start such initiatives.
of BtB plant was of 730 MW. In the second case the BtB
The results of preliminary investigation of power system
operating power was determined by new power flow in the
emergency control efficiency with the use of the BtB
hybrid tie and was of 636 MW. It is significant that the BtB
converter station at Heihe are shown in Fig. 4 and Table I
converter station was represented by the one bridge model. It
borrowed in [3].
was stipulated by some problems with simulating two bridges
model. However, in our opinion, such approach is admissible
at this phase of the investigation. TABLE I
In addition to Heihe BtB converter station, the impending RESULT OF SIMULATION: HEIHE BTB EMERGENCY CONTROL
Generator Load
Siberian BtB converter stations were represented. One of them Control actions
rejection, MW shedding, MW
will be located at southern 220 kV transmission systems while
another one has to be constructed at northern 220 kV tie as it GR+RLS+DB(ω1) 2 x 225 240
shown in Fig. 2. The first BtB converter station was modeled GR+RLS+DB(ω -ω ) 3 x 225 170
1 2
5
(A) Braking under Zeya rotor speed stability keeping, given in Table I, allow concluding that
280 800 utilization of the mutual speed for the BtB converter station
180 600 improves efficiency of the control. It seems that the
W)
? (deg)80 400ower (M ccihracnunmeslsta onfc ed artaai streasn simncirsesaiosned b urte qthueir eremqeunirtes mfeonr t hciogrhre ssppoenedd
-20 200P
to the modern tendency of the use of WAMS/WACS
-120 0 technologies in power systems.
0 1 2 3 4 5 6 7 8
Time (sec) B. BtB generally accepted model
(B) Braking under Zeya-Vladivostok mutual speed
The simulation results, borrowed in [7], are combined into
280 800
Fig. 5 and Fig. 6. The A curves of the each columns give us
180 600
W) the possibility to imagine the moments of commutation
δ (deg)-2800 240000Power (M s0t.i1p2u lsaetce,d 2b)y s u1b) spehqauseen-tt ot-rpanhsamsei-sgsrioounn ldin fea utrlitp wpiinthg ,d aunrdat i3o)n t hoef
-120 0 transmission line auto-reclosing in 1 sec. In addition, it shows
0 1 2 3 4 5 6 7 8 behaviour of the voltage during the transient. B and C curves
Time (sec)
of the columns illustrate the angle differences both at the
— Zeya-Vladivostok angles difference
— Luchegorsk-Vladivostok angle difference Russia and China correspondingly. D and E curves produce
— Vladivostok Thermal Power Plant rotor angle both the firing angle for the rectifier and the extinction angle
— Heihe BtB power
for the inverter. Left column of each figures illustrate the
Fig. 4. Emergency control with the use of BtB converter station braking
power system response in the case of absence of AC ties in
the interface, while right column correspond to presence of
Fig. 4 presents the power system transients with
emergency control that is based on the rotor speed of the Zeya AC transmission line in the interface. Fig. 5 relates to the case
HPP generators as input parameter and the Zeya HPP- of the faults at the Russian side, but Fig. 6 has to do with the
Vladivostok SPP mutual rotor speed, respectively. The results fault at the Chinese side of the interconnection. Such
of the two latter simulations allow concluding that it is representation of the information, in our opinion, gives us
possible to use BtB converters for emergency control and that possibility to compare with each other the various situations
it constitutes a feasible alternative to the dynamic braking examined in the paper.
systems used at Zeya HPP. One can see that dynamic stability Analysis of the results gives us some interesting subject
is kept by using BtB active power modulation for emergency for discussion. Firstly, one can see that the oscillation
control. The volumes of load shedding, that should be used for behavior of the power grids is differing fundamentally.
Fig. 5. Simulation results for the case of the short circuit in the Russian Far East Fig. 6. Simulation results for the case of the short circuit in China North-East
Power Grid: A, A' - voltage at the short circuit node; B, B' - angle differences in Power Grid: A, A' - voltage at the short circuit node; B, B' - angle differences
Russia side(▬ Nerungry SPP and Vladivistok SPP rotor angles; ▬ Zeya HPP in Russia side(▬ Nerungry SPP and Vladivistok SPP rotor angles; ▬ Zeya
and Vladivistok SPP rotor angles; ▬ Bureya HPP and Vladivistok SPP rotor HPP and Vladivistok SPP rotor angles; ▬ Bureya HPP and Vladivistok SPP
angles); C, C' - angle differences in China side (▬ Quinlin and Hexin equivalent rotor angles); C, C' - angle differences in China side (▬ Quinlin and Hexin
generators; ▬ Fangzhen and Hexin equivalent generator; ▬ Daqing and Hexin equivalent generators; ▬ Fangzhen and Hexin equivalent generator; ▬
equivalent generator); D, D' - firing angle (alpha); E. E' - extinction advance Daqing and Hexin equivalent generator); D, D' - firing angle (alpha); E. E' -
angle (gamma). extinction advance angle (gamma).
6
Prolonged oscillations can take place in the Russian Far East VI. REFERENCES
Interconnected power system under the faults in the 500 KV [1] UCTE-IPS/UPS Project News. Available: http://www.ucte-
power network, whereas the decrement of oscillation in the ipsups.org/news/e_default.asp#20081208
Chinese part is much better. Secondly, there is the appreciable [2] Stubbe M., Bihain A., Baader J.C. et al., “STAG – A New Unified
Software Program for the Study of the Dynamic Behavior of Electrical Power
influence of AC 220 kV transmission line that shunts the BtB
System”, Engineering Review , IEEE, February 1989.
converter station onto frequency oscillations in Chinese part [3] E. Kosterina, A. Arestova, M. Balabin et. al., “The Use of Special
under the fault appearing in the Russian part of the Tools for Emergency Control in the Russian Far East Power Grid”, Proc.
PowerCon, New Delhi, 2008.
interconnection. Thirdly, the regular automatic of the BtB
[4] N. Bondareva, D. Kolotovkin, R. Cherkaoui et al., “Comparison of
converter station gives a good quality of control only for the the Results of Full-scale Experiment and Long Term Dynamics Simulations in
case of asynchronous interconnection. the Siberian Interconnected Power System”, Bulk Power System Dynamics
and Control – VI, August 22-27, 2004, Cortina d’Ampezzo, Italy.
[5] Ding, H., Han, M.X., Chen, Q. et al., “Detailed modeling of China-
V. CONCLUSION Russia Heihe back-to-back HVDC project using PSCAD/EMTDC”, Electric
Utility Deregulation and Restructuring and Power Technologies, 2008. DRPT
Hybrid interstate ties can possess indisputable advantage
2008, Nanjing
over asynchronous ones because of new opportunity for [6] A. Arestova “Application of BtB converter stations potential to
power system regimes control given by FACTS devices. This improve UCTE-IPS/UPS interconnection”, Proc. IYCE 2009, Budapest, 2009.
circumstance is relevant also for traditional BtB converter [7] A. Grobovoy, Y. Grishin, I. Kolosok “Practicability of SPS
Coordination in Market Environment for Impending UCTE-IPS/UPS
stations on the base of the so-called current source converters
Interconnection”, the 2nd CIGRE/IEEE PES Internacional Symposium
(CSC). The influence of the SVC control system on the Congestion Management in a Market Environment, San-Antonio, 2005.
dynamic behavior of the asynchronous or hybrid tie between
Russian and Chinese power grids could be the subject of the VII. BIOGRAPHIES
near future investigation. However, just now one can assume,
that the combined use of the potential of AC and DC Andrey Grobovoy (M’01) was born in the Ukraine,
former USSR, in 1950. He graduated from the Far
technologies can become by fundamental factor for rapid
East Polytechnic Institute, Vladivostok, in 1973.
development of electricity industry. After conscription, since 1975 his employment
Also the next stage of the study has to become the experience includes Siberian Electric Power
Research Institute. Since 1992, he is general director
examination of WAMS/WACS technologies implementation
of Power System Emergency Control Laboratory.
for damping of the frequency oscillation shown in Fig. 5, C’. His special field of interests includes large power
Indeed, Heihe BtB converter station is the first stage of the system control, monitoring and simulation.
wide-ranging cooperation in the area electricity market. This
Anna Arestova (M’09) was born in Kazakhstan,
fact assumes creation several power plants in Siberia and the
former USSR, in 1987. She received the rank of the
Russian Far East for electricity supplying to North and expert in power systems, with honors, from
Central China. In the case of realization of the hybrid ties the Novosibirsk State Technical University in 2009.
additional control tools can be needed. One of them could Since 2008 she is researcher of Power System
Emergency Control Laboratory. Her research
become the BtB active power modulation. Taking into
interests include large power system control,
account that the present investigation did not covered above monitoring and simulation.
mentioned SPS structures one can assume that the next step
in this direction have to become exploration of the Heihe BtB
Yuriy Sidorkin was born in former German
emergency control potential.
Democratic Republic in 1947. He graduated from
On the other hand, the chance of appearance of the same Novosibirsk State Technical University in 1970. He
low frequency oscillation in UCTE-IPS/UPS unites the received his PhD degree in Power Systems in 1975.
The ranks of associate professor and professor were
interest of European, Russian, and Chinese electrical
given to him in 1981 and 1998 correspondingly.
engineers. This project is the convenient case for Since 1979 he is Dean of the Power Engineering
international cooperation between EC, Russian and Chinese faculty. His special field of interests includes
researches in the area of BtB and WAMS/WACS optimization of power network regimes.
technologies. With all this going on, good basis for common
EC-Russia-China investigation can become the use of
EUROSTAG software. Reciprocation in these areas meets the
requirements of all possible participants of such international
cooperation.
