[0001] The present invention relates to a method for controlling an air-cooled condenser
of an electric power generation plant with optimized management of state transitions
and to an electric power generation plant.
[0002] EP 0004448 discloses such an electric power plant according to the preamble of claim 11 and
a method for controlling its air-cooled condenser according to the preamble of claim
1.
[0003] As known, the combined cycle plants for generating electric power can have different
configurations, according to project needs. In any case, a combined cycle plant comprises
at least one gas turbine and a steam turbine, one or more electric generators, a recovery
boiler and a condenser.
[0004] The recovery boiler receives hot exhaust gases from the gas turbine and utilizes
them for producing steam in appropriate conditions to be supplied to different sections
(high, medium and low pressure) of the steam turbine.
[0005] The condenser is generally of the air type (ACC, Air-Cooled Condenser) and condenses
the steam deriving from the steam turbine or from by-pass systems with which steam
turbines are normally provided, transferring the remaining air (non-condensable gases)
into the atmosphere.
[0006] An air-cooled condenser typically comprises a plurality of tube bundle lines, in
which the steam flows, and a plurality of fans, organized as a matrix in rows and
columns and arranged so as to cool the steam flowing through the tube bundles.
[0007] The major fraction (about 90%) of the steam is condensed into tube bundles by fans
belonging to primary modules and then collected, by gravity, into a collection tank.
The condensate will then be taken from the collection tank thorugh extraction pumps
and sent to the recovery boiler. The remaining fraction (about 10%) of the steam is
condensed in tube bundles cooled by fans belonging to sub modules ("dephlegmators")
and the residual air (non-condensable gases) is conveyed to an air extraction system,
to be evacuated into the atmosphere.
[0008] The cooling action required of the condenser naturally varies depending both on the
power supplied by the plant (electrical load), and the environmental conditions (pressure
and temperature). The intensity of the cooling depends on the number of fans and by
their speed, which must be properly controlled. The fans, in particular, can be switched
off or operated at constant speed, selected in a set of values.
[0009] The monitoring operations are critical, however, due to the high power absorbed by
each fan (often several tens of kilowatts). Turning on a fan, for example, involves
the absorption of a high current peak, as well as the increase or decrease of speed.
It is possible therefore that overloads may occur for the medium/low voltage transformers
that power the motors of the fans. Other important aspects to consider are the proper
demagnetization of the motors while changing speeds and the coupling among the mechanical
parts of the motor gear unit in the transition from high to low speed.
[0010] On the other hand, it is necessary that the transition between different states of
the air condenser is quickly completed. A too slow response of the condenser, in fact,
would have a negative impact on the entire system performance and limit its ability
to respond, for example, in the event of blockage of the steam turbine. In this case,
the flow rate of steam flowing through the by-pass, increased by the temperature leveling
water, causes an abrupt temporary increase in steam pressure in the condenser. If
the pressure increase is not offset by a rapid increase in the number of fans in service,
it could lead to the quick closing of the bypass and therefore the blockage of the
gas turbine can occur.
[0011] The aim of the present invention is therefore to provide a control method for an
air-cooled condenser of an electric power generation plant and an electric power generation
plant that allows efficient and secure state transition management of the condenser.
[0012] According to the present invention a method for controlling an air-cooled condenser
of an electric power generation plant and an electric power generation plant are provided,
as defined respectively in claims 1 and 11.
[0013] The present invention will now be described with reference to the annexed drawings,
which illustrate a non limitative example of an embodiment, in which:
- Figure 1 is a simplified block diagram of an electric power generation plant incorporating
a condenser according to an embodiment of the present invention;
- Figure 2 is a simplified front view of a part of the condenser of Figure 1 sectioned
along the traced plane II-II of figure 4;
- Figure 3 is a simplified side view of a part of the condenser of Figure 1 sectioned
along the traced plane III-III of figure 4;
- Figure 4 is a simplified plan view from above of part of the condenser of figure 1;
- Figure 5 is a simplified block diagram relative to a portion of the condenser of figure
1;
- Figure 6 illustrates a table relative to the operation of the condenser of figure
1;
- Figure 7 is a flowchart relative to the method steps for controlling an air condenser
according to an embodiment of the present invention;
- Figure 8 is a graph that represents magnitudes used in the method steps illustrated
in Figure 7;
- Figure 9 is a flowchart concerning further method steps of figure 1;
- Figure 10 is a flowchart relative to the method steps for controlling an air condenser
according to a different embodiment of the present invention; and
- Figure 11 is a flowchart relative to the method steps for controlling an air condenser
according to a further embodiment of the present invention.
[0014] As shown in Figure 1, a combined cycle plant for generating electric power comprises
a gas turbine assembly 2, a steam turbine 3, two alternators, 4, 5, respectively,
coupled to the gas turbine 2 and the steam turbine 3, a recovery boiler 7, which operates
as a steam generator, a condenser 8, an acquisition module 9 and a control device
10.
[0015] The gas turbine assembly 2 comprises a compressor 11, which draws a flow rate of
air from outside through an intake duct not shown, a combustion chamber 12 and a gas
turbine 13, coupled to the combustion chamber 12 for receivig and expanding a flow
rate of exhaust gas. The exhaust gas of gas turbine 2 are conveyed towards the recovery
boiler 7 and are used for producing steam.
[0016] The steam turbine 3, which in the described example comprises a high pressure section
3a and a medium-low pressure section 3b, receives high pressure and low-medium pressure
steam flow rates from the recovery boiler 7 and provides a steam flow rate to the
condenser 8 through the exhaust of medium-low pressure section 3b and through a by-pass
system of a known type and not shown here for simplicity.
[0017] The condenser 8 is of the air type (forced ventilation). Through a controlled flow
of forced cooling air, the condenser 8 cools the steam received by the steam turbine,
causing condensation. The flow of cooling air is determined by the control device
10.
[0018] The condensed steam is conveyed to a storage tank 15 and then withdrawn by condensate
extraction pumps 16 to be fed again to the recovery boiler 7.
[0019] The control device 10 has a plurality of processing units, assigned respectively,
to the gas turbine control group 2, to the steam turbine 3, and to the condenser 8
and cooperating with each other to regulate the power delivered by the plant 1. In
particular the processing units 18, 19 for the control of the gas turbine 2 and of
the steam turbine 3 are of a known type and will not be described in detail. A further
processing unit 20, in charge of the control of the condenser 8, receives from the
acquisition module 9 a pressure signal P
A, indicative of the absolute pressure at the inlet of the condenser 8 and uses it
to determine and set appropriate conditions for the condenser 8. The structure of
the processing unit 20 and the methods of management of the operating conditions of
the condenser 8 will be later described in detail.
[0020] Figures 2-4 illustrate in simplified form the condenser 8, which comprises a base
21 and a plurality of fans F
11, F
12, ..., F
1N' F
21, F
22, ..., F
2N, F
M1, F
M2, ..., F
MN (designated in synthesis for this purpose by way of the symbol F
IJ), supported by the base 21. The fans F
IJ are disposed as a matrix and are grouped into M side by side lines, also known as
"paths" ST
1, ST
2, ..., ST
M, of each N fans (for example 7 paths of 6 fans). Tube bundles 22 (which are shown
in Figure 4 are only hatch indicated, for simplicity), are traversed by the steam
coming from the steam turbine 3 and are arranged along respective paths ST
1, ST
2, ..., ST
M, in order to receive air from the fans F
IJ.
[0021] The fans F
IJ are driven by respective motors M
11, M
12, ..., M
1N, N
21, M
22, ..., M
2N, M
M1, M
M2, ..., M
MN (schematically illustrated in Figure 5 and designated in synthesis for this purpose
by way of the symbol M
IJ), which are in turn supplied by transformers of medium voltage/low voltage. In the
non-limitative example here described, there are two transformers 24, 25. For example,
the motors M
IJ of fans F
IJ in odd-positions in respective paths S
I are supplied by the transformer 24; and the motors M
IJ of fans F
IJ in even-positions in respective paths are supplied by the transformer 25.
[0022] With reference once again to Figure 1, the processing unit 20 assigned to the control
of the condenser 8 comprises a reference generator module 26, a subtractor node 27,
a state management module 28, a memory module 29 and a drive module 30.
[0023] The reference generator module 26 is programmable in order to provide a reference
pressure value P
R, indicative of a target steam pressure obtainable at entrance to the condenser 8.
[0024] The subtractor node 27 determines a pressure error E
P on the basis of the difference between the pressure signal P
A and the value of reference pressure P
R (i.e. Ep = P
A - P
R or, alternatively, Ep = K (P
A - P
R), where K is a constant). The pressure error E
P is supplied to the state management module 28 and used here for determining and changing
the operating conditions of the fans F
IJ.
[0025] The operating conditions of the fans F
IJ are encoded using a table 31 contained in the memory module 29 and illustrated by
way of example in Figure 6. The table 31 has P rows and MxN columns. Each row of the
table 31 defines one of H available states S
1, ..., S
P (in synthesis S
K) of the condenser 8, i.e. a particular configuration of operating conditions of the
fans F
IJ. Instead, the columns of table 31 define the operating conditions of respective fans
F
IJ in each state. Therefore, each cell defines the operating conditions of a specific
fan F
IJ in a specific state of the condenser 8.
[0026] Each fan F
IJ can be selectively placed in one of a plurality of operating conditions, which comprise
a state of isolation (wherein the fan stopped and the line of tube bundles is intercepted
by specific isolation valves, in order to reduce the heat-exchange surface in winter
conditions and to avoid, therefore, the formation of ice in the tubes), a condition
of natural convection (fan stopped) and a plurality of speed values R
1, ..., R
Q (for example, expressed in revolutions per minute). In the embodiment described,
the fans F
IJ are operable at a low speed R
1 and at a high speed R
2. For example, the low speed R
1 is equal to 75% of the high speed R
2.
[0027] In Figure 6, the possible operating conditions of the fans F
IJ are represented as follows:
N: natural convection (fan stopped)
R1: low speed
R2: high speed.
[0028] The procedure used by the state management module 28 will be later described in detail.
Practically, the state management module 28 determines in which state S
K the condenser 8 must be reached or maintained.
[0029] A signal indicative of the selected state S
K is sent to the drive module 30, which controls the motors M
IJ of the fans F
IJ accordingly. In particular, if the state management module 28 requires a change of
state, the drive module 30 manages the transition to the state S
K in order to avoid overloading for the transformers 24, 25 and problems connected
with demagnetization of motors M
IJ.
[0030] With reference to Figure 7, the procedure performed by the state management module
28 is based on the verification of conditions on the pressure error value E
P, on its integral I and on the derivative of the absolute pressure P
A (represented by way of example in Figure 8). If neither of the conditions are verified,
the state management module 28 determines a state change in order to increase or decrease
the cooling action of the condenser 8.
[0031] In one embodiment, the following conditions are verified:
C
2 : TH
L < I < TH
H, with I = ∫ K
IE
Pdt
[0032] In addition, a further condition is verified relative to the concordance between
the sign of the pressure error E
P as defined in (E
P = P
A - P
R or E
P = K (P
A - P
R) ) and the sign of the derivative of the absolute pressure P
A.
[0033] The parameters α
L1, α
H1, respectively negative and positive, define in practice a dead band B
E around the value zero for the pressure error E
P (or, in a completely equivalent way, around the reference pressure value P
R for the absolute pressure P
A) and are preferably programmable.
[0034] In the expression relative to the condition C
2, the integration constant K
I determines the rapidity of response of the state management module 28 and is calibratable,
while the parameters TH
L and TH
H are respectively a negative threshold and a positive threshold and set a dead band
B
I around the value zero for the integral I.
[0035] Evidently, the above expressed conditions can be explicitly formulated in terms of
absolute pressure P
A and of the reference pressure value P
R:
[0036] Even in this case a further condition is verified relative to the concordance between
the sign of the error in pressure E
P as defined in (E
P = P
A - P
R or E
P = K (P
A - P
R) ) and the sign of the derivative of the absolute pressure P
A.
[0037] Initially (Figure 7 block 100), a current state S
K is selected and the state management module 28 performs a test on the condition C
1 until this is verified (block 100, silicon exit). When the condition C
1 is no longer verified, i.e. when the absolute pressure P
A exits the dead band B
E (Figure 7, block 100, exit NO, Figure 8), the state control module 28 initializes
an integrator (Figure 7, block 105) which calculates the integral I (block 110).
[0038] The test on the condition C
1 (block 115) is then executed once again. If the condition C
1 is verified (block 115, exit YES), the procedure starts again from block 100, otherwise
(block 115, exit NO) the state management module 28 performs a test on the condition
C
2, to check if the integral I is comprised between the negative threshold TH
L and the positive threshold TH
H (Figure 7, block 120, Figure 8). If affirmative (Figure 7, block 120, exit YES),
the value of the integral I is updated (block 110) and the test on the condition C
1 (block 115) is repeated. If the integral I is out of the dead band B
I between the negative threshold TH
L and the positive threshold TH
H (Figure 7, block 120, exit NO, Figure 8), the state control module 28 performs a
test on the concordance between the sign of the pressure error E
P and the sign of the derivative of the absolute pressure P
A (block 125). If the pressure error E
P and the derivative of the absolute pressure P
A are both positive (block 125, exit YES), the state control module 28 selects a new
state S
K', to which corresponds a higher cooling action of the condenser 8 compared to the
current status S
K (block 130). In this case, in fact, the absolute pressure P
A is greater than the reference pressure P
R and is increasing (positive derivative). Therefore, also the magnitude of the pressure
error E
P grows and it is necessary to increase heat dispersion by way of increased ventilation.
The magnitude of the cooling action is determined by the number of active fans F
IJ and their speed.
[0039] On the contrary (block 125, exit NO), the state control module 28 performs an additional
test on the concordance between the sign of the pressure error E
P and the sign of the derivative of the absolute pressure P
A (block 135).
[0040] In particular, if the pressure error E
P as defined and the derivative of the absolute pressure P
A are both negative (block 135, exit YES), the state control module 28 selects a new
state S
K' , which corresponds to a lower cooling action of the condenser 8 (block 140). The
absolute pressure P
A is in fact lesser than the reference pressure P
R and is also diminishing (negative derivative). Therefore, the amplitude (absolute
value) of the pressure error E
P grows and is necessary to reduce the heat dispersion by way of lesser ventilation.
[0041] On the contrary (block 135, exit NO), the amplitude (absolute value) pressure error
E
P is reducing, since the sign of the pressure error E
P and the sign of the derivative of the absolute pressure P
A are not in accordance. In this case, the procedure continues from block 110, i.e.
a new value of the integral I is calculated and the test is repeated on the condition
C
1 (block 115) .
[0042] Once the new state S
K' is selected, the state management module 28 inhibits the updating of the integral
until the transition to the new state S
K' is completed (block 145). Therefore, the updating of the integral I is once again
permitted, and the procedure ends.
[0043] As mentioned above, the drive module 30 receives a request to modify the state of
the condenser 8 switching to state S
K', to which corresponds a different cooling action, and acts upon the fans F
IJ in order to bring them under the operating conditions corresponding to the state
S
K'.
[0044] In one embodiment, the procedure to actuate the change of state is performed as shown
in Figure 9.
[0045] Upon receipt of the request to bring the condenser 8 from the current state S
K to the new state S
K' (block 200), the drive module 30 selects the fans F
IJ whose operating conditions must be modified (block 205) and determines the order
for intervention upon the selected fans F
IJ (block 210).
[0046] The selection can be simply made by comparing the rows of the table 31 of Figure
6 corresponding to the states S
K and S
K'. Similarly, the final operating conditions are determined for each fan that has
to change modes.
[0047] The order of intervention upon the fans F
IJ is however preferably determined so as to turn on the first fans belonging to the
secondary modules ("dephlegmators") of the condenser 8 with respect to those belonging
to primary modules and in general maintaining as much as possible the heat exchange
conditions uniform throughout the entire condenser 8. For example, first to be modified
is the speed of fans F
IJ placed in even positions in the central paths ST
1, ST
2, ..., ST
M and gradually the others.
[0048] Therefore, if there are fans F
IJ that need to be brought to a stopped condition, they are stopped at the same time
(block 215). Oppositely, if at this step there are fans F
IJ that need to be started from the stopped condition, the drive module 30 puts them
in function in sequence according to the speed shown in Table 31. More specifically,
the drive module 30 simultaneously starts groups of no more than N
MAX of fans F
IJ and interpose a start-up time range T
S between the start of a group of fans F
IJ and the next (N
MAX is the maximum number of fans F
IJ that can be started at the same time without overloading the transformers 24, 25).
[0049] The drive module 30 then intervenes upon the already active fans F
IJ, the speed R
1, ..., R
L of which needs to be changed. A number of fans F
IJ not greater than N
MAX are stopped (block 220), while the others remain functioning in unchanged operating
conditions. After a minimum rest time T
R has elapsed (block 225), the stopped fans F
IJ are reactivated at a speed R
1, ..., R
L required in the new state S
K' (block 230). The rest time T
R can be shorter when a transition of a fan F
IJ is required at a higher speed R
1, ..., R
L than a transition at a lower speed R
1, ..., R
L. In addition, the rest time is related to the demagnetization time of motors M
IJ, so as to allow the correct demagnetization.
[0050] If all of the fans F
IJ are driven at the expected speed for the new state S
K' (block 235, exit YES), the drive module 30 notifies the state management module
28 that the transition to the new state S
K' has been completed (block 240) . On the contrary (block 235, exit NO), a new group
of no more than N
MAX fans F
IJ and is stopped (block 220) to be restarted at a speed R
1, ..., R
L provided for the new state S
K' (block 230), after the rest time T
R (block 225) elapses. In this way, practically, while a group of fans F
IJ are started at a predefined speed, another group of fans F
IJ are stopped. The start-up and shutdown steps of these groups of fans F
IJ may be substantially simultaneous.
[0051] In this way, it is possible to make a transition between states in reduced time,
avoiding however critical situations due to high inrush power absorbed by the fans.
In particular, by limiting the number of fans started simultaneously the transformers
24, 25 are not overloaded. In addition, the waiting pause in the speed transition
allows to properly demagnetize the motors M
IJ of fans F
IJ and to preserve the mechanical parts, especially the gear units, which may otherwise
be too stressed.
[0052] Figure 10, wherein equal steps to those already described above are indicated with
the same reference numbers, shows a procedure used by the state management module
28 in an alternative embodiment of the invention.
[0053] In this case, in addition to conditions C1, C2 and the concordance condition of sign
of pressure error E
P and of the derivative of the absolute pressure P
A above indicated, the state management module 28 utilizes a further condition C
0 on the error, defined as follows:
where α
L2 ∈ ( [ - 1, α
L1] and α
H2 ∈ ( [α
H1, 1] (e.g., α
L1 = -0.4 and α
H1 = 0.4). Practically therefore, a safety band B
S is defined around the value of the reference pressure P
R, comprising and being wider than the dead band B
E (see also Figure 8).
[0054] In the embodiment of figure 10, the state management module 28 cyclically monitors
the condition C
1 (block 100). When the condition C
1 ceases to be verified, the control module 28 initializes the integrator (block 105)
and performs a test on the condition C
0 (block 150). The value of the integration constant K
I is determined by the outcome of the test. In particular, an initial value of integration
K
IL is assigned to the integration constant K
I (block 155), if the condition C
0 is verified (block 150, exit YES), and a second value of integration K
IH (block 160), greater than the first value of integration K
IL, is assigned otherwise (block 150, exit NO) .
[0055] Practically, if the absolute pressure P
A exceeds the safety band B
S, the responsiveness of state management module 28 is increased, so as to promptly
cause a change of state.
[0056] The procedure then continues as described above, besides the fact that the test on
the condition C
0 (block 150) and the assignment of the constant of integration (blocks 155 and 160)
are repeated until the situation persists in which the condition C
1 is not verified, while the condition C
2 and conditions concerning the concordance of sign of the pressure error E
P and of the derivative of the absolute pressure P
A are verified.
[0057] Figure 11 illustrates a procedure performed by the state management module 28 in
a further embodiment of the invention. Also in this case, a test is executed on the
condition C
0 as defined above (block 175), after the integrator is initialized (block 105). If
the absolute pressure P
A is within the safety band B
S (block 175, exit YES), the procedure continues as described with reference to Figure
9, with the tests on conditions C1, C2 and on the concordance of sign of the pressure
error E
P and derivative of the absolute pressure P
A (blocks 115, 120, 125, 135). If, on the contrary, the absolute pressure P
A exceeds the security band B
S (Block 175, exit NO), a new state S
K' is immediately selected, depending on whether the pressure error E
P is positive or negative. More precisely, if the pressure error E
P is positive (block 180, exit YES), the state control module 28 selects a new state
S
K', which corresponds to a higher cooling action of the condenser 8 (block 130). If
instead the pressure error E
P is negative (block 180, exit NO), the state control module 28 selects a new state
S
K' , which corresponds to a lower cooling action of the condenser 8 (block 140).
[0058] It is finally clear that modifications and variations can be made to the method and
plant described, without going beyond the scope of the present invention, as defined
in the appended claims.
[0059] In particular, the invention can be advantageously applied to any type of plant based
on a steam turbine, such as plants in a "single-shaft" configuration (with gas turbine
and steam turbine coupled to the same shaft), and in a "2+1" configuration (with two
gas turbines).
[0060] In addition, the steam turbine may have medium pressure and low pressure separated
sections.
1. Method for controlling an air-cooled condenser of an electric power generation plant,
wherein the condenser (8) comprises a plurality of fans (F
IJ) and a control device (10), configured to select a state (S
K, S
K') of the condenser from among a plurality of available states (S
1, ..., S
P), defined by sets of speed values (R
1, ..., R
Q) of the fans (F
IJ) :
the method comprising:
receiving a request to modify a selected current state (SK);
selecting a new state (SK') in response to the request;
modifying the speed (R1, ..., RQ) of at least one of the fans (FIJ) from a first speed value (R1, R2) to a second speed value (R2, R1) in accordance with the selected new state (SK') ;
the method being characterized in that modifying the speed (R1, ..., RQ) comprises:
stopping the at least one fan (FIJ):
waiting a rest time interval (TR) after stopping; and
starting the stopped fan (FIJ) at the second speed value (R2, R1).
2. Method according to claim 1, wherein the fans (F
IJ) are operated by respective electric motors (M
IJ), supplied by at least one transformer (24, 25) and comprising:
determining a maximum number (NMAX) of fans (FIJ) which can be started simultaneously without overloading the transformer (24, 25).
3. Method according to claim 2, wherein the rest time interval is correlated to a demagnetization
time of the motors (MIJ).
4. Method according to claim 2 or 3, wherein the rest time interval (TR) has a first duration, if the first speed value (R1, R2) is greater than second speed value (R2, R1), and a second duration, not greater than the first duration, if the first speed
value (R1, R2) is lower than the second speed value (R2, R1).
5. Method according to any one of claims from 2 to 4, wherein modifying the speed (R
1, ..., R
Q) comprises:
stopping a plurality of fans (FIJ); and
simultaneously starting, after the rest time interval (TR), a number of fans (FIJ) not greater than the maximum number (NMAX).
6. Method according to claim 5, wherein arresting a plurality of fans (FIJ) comprises simultaneously stopping a number of fans (FIJ) not greater than the maximum number (NMAX), while operative conditions of the other fans (FIJ) are kept unchanged.
7. Method according to claim 5 or 6, wherein the steps of stopping a plurality of fans
(FIJ) and of simultaneously starting, after the rest time interval (TR), un number of fans (FIJ) not greater than the maximum number (NMAX) are repeated until all the fans (FIJ) are operated at the respective second speed values (R2, R1) in accordance with the new state (SK').
8. Method according to any one of claims from 5 to 7, wherein the steps of stopping a
plurality of fans (FIJ) and of simultaneously starting, after the rest time interval (TR), un number of fans (FIJ) not greater than the maximum number (NMAX) are carried out in a substantially simultaneous way.
9. Method according to any one of claims from 5 to 8, wherein at least some of the fans
(FIJ) are at rest in the current selected state (SK) and are operated at a respective speed (R1, ..., RQ) in the selected new state (SK') and wherein modifying the speed (R1, ..., RQ) of at least one of the fans (FIJ) comprises starting the fans (FIJ) which are at rest in the current state (SK) in groups having a number of elements not greater than the maximum number (NMAX).
10. Method according to claim 9, wherein between the start of a group of fans (FIJ) which are at rest in the selected current state (SK) and the start of the subsequent group of fans (FIJ) which are at rest in the selected current state (SK) a start time interval is interposed.
11. Electric power generation plant comprising:
a steam turbine (3);
an air-cooled condenser (8), coupled to the steam turbine (3), for receiving steam
coming from the steam turbine (3), and including a plurality of fans (FIJ) and a control device (10);
wherein the control device (10) is configured to:
select a state (SK, SK') of the condenser from among a plurality of available states (S1, ..., SP), defined by sets of speed values (R1, ..., RQ) of the fans (FIJ) ;
receive a request to modify a selected current state (SK);
select a new state (SK') in response to the request;
modifying the speed (R1, ..., RQ) of at least one of the fans (FIJ) from a first speed value (R1, R2) to a second speed value (R2, R1) in accordance with the selected new state (SK') ;
characterized in that the control device (10) is further configured to:
stop the at least one fan (FIJ) ;
wait a rest time interval (TR) after stopping; and
start the stopped fan (FIJ) at the second speed value (R2, R1).
12. Plant according to claim 11, wherein the fans (FIJ) are operated by respective electric motors (MIJ) supplied by at least one transformer (24, 25) and wherein the rest time interval
is correlated to a demagnetization time of the electric motors (MIJ).
13. Plant according to claim 12, wherein the rest time interval (TR) has a first duration, if the first speed value (R1, R2) is greater than the second speed value (R2, R1), and a second duration, not greater than the first duration, if the first speed
value (R1, R2) is lower than the second speed value (R2, R1).
14. Plant according to claim 12 or 13, wherein the control device (10) is further configured
to:
stop a plurality of fans (FIJ); and
simultaneously starting, after the rest time interval (TR), a number of fans (FIJ) not greater than a maximum number (NMAX) of fans (FIJ) which can be simultaneously started without overloading the transformer (24, 25).
15. Plant according to claim 14, wherein the control device (10) is further configured
to simultaneously stop a number of fans (FIJ) not grater than the maximum number (NMAX) and at the same time keeping unchanged operating conditions of the other fans (FIJ).
1. Verfahren zum Steuern eines luftgekühlten Kondensors einer Stromkraftwerksanlage,
wobei der Kondensor (8) mehrere Ventilatoren (F
IJ) und eine Steuervorrichtung (10) umfasst, die konfiguriert ist, einen Zustand (S
k, S
k') des Kondensors unter mehreren verfügbaren Zuständen (S
1, ..., Sp), die durch einen Satz von Drehzahlwerten (R
1, ..., R
Q) der Ventilatoren (F
IJ) definiert sind, auszuwählen;
wobei das Verfahren umfasst:
Empfangen einer Anfrage, um einen ausgewählten aktuellen Zustand (Sk) zu modifizieren; Auswählen eines neuen Zustandes (Sk') als Reaktion auf die Anfrage;
Modifizieren der Drehzahl (R1, ..., RQ) von mindestens einem der Ventilatoren (FIJ) von einem ersten Drehzahlwert (R1, R2) auf einen zweiten Drehzahlwert (R2, R1) entsprechend dem gewählten, neuen Zustand (Sk');
wobei das Verfahren dadurch gekennzeichnet ist, dass das Modifizieren der Drehzahl (R1, ..., RQ) umfasst:
Stoppen des mindestens einen Ventilators (FIJ);
nach dem Stoppen Warten für die Dauer eines Ruhezeitintervalls (TR); und
Starten des gestoppten Ventilators (FIJ) mit dem zweiten Drehzahlwert (R2, R1).
2. Verfahren nach Anspruch 1, wobei die Ventilatoren (F
IJ) durch jeweilige elektrische Motoren (M
IJ), die von mindestens einem Transformator (24, 25) versorgt werden, betrieben werden,
und wobei das Verfahren umfasst:
Bestimmen einer maximalen Anzahl (NMax) von Ventilatoren (FIJ), die ohne Überlastung der Transformatoren (24, 25) gleichzeitig gestartet werden
können.
3. Verfahren nach Anspruch 2, wobei das Ruhezeitintervall mit einer Entmagnetisierungszeit
der Motoren (MIJ) korreliert ist.
4. Verfahren nach Anspruch 2 oder 3, wobei das Ruhezeitintervall (TR) eine erste Dauer, wenn der erste Drehzahlwert (R1, R2) größer als der zweite Drehzahlwert (R2, R1) ist, und eine zweite Dauer, die nicht größer als die erste Dauer ist, wenn der erste
Drehzahlwert (R1, R2) kleiner als der zweite Drehzahlwert (R2, R1) ist, aufweist.
5. Verfahren nach einem der Ansprüche 2 bis 4, wobei das Modifizieren der Drehzahl (R
1, ..., R
Q) umfasst:
Stoppen mehrerer Ventilatoren (FIJ); und
nach dem Ruhezeitintervall (TR) gleichzeitig Starten einer Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) ist.
6. Verfahren nach Anspruch 5, wobei das Bremsen mehrerer Ventilatoren (FIJ) ein gleichzeitiges Stoppen einer Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) ist, umfasst, während die Betriebsbedingungen der anderen Ventilatoren (FIJ) unverändert gehalten werden.
7. Verfahren nach Anspruch 5 oder 6, wobei die Schritte des Stoppens mehrerer Ventilatoren
(FIJ) und des gleichzeitigen Startens einer Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) ist, nach dem Ruhezeitintervall (TR), wiederholt werden, bis alle Ventilatoren bei den jeweiligen zweiten Drehzahlwerten
(R2, R1) gemäß dem neuen Zustand (Sk') betrieben werden.
8. Verfahren nach einem der Ansprüche 5 bis 7, wobei die Schritte des Stoppens mehrerer
Ventilatoren (FIJ) und des gleichzeitigen Startens einer Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) ist, nach dem Ruhezeitintervall (TR), in einer im Wesentlichen gleichzeitigen Art ausgeführt werden.
9. Verfahren nach einem der Ansprüche 5 bis 8, wobei sich mindestens einige der Ventilatoren
(FIJ) in dem ausgewählten aktuellen Zustand (Sk) in Ruhe befinden und in dem gewählten, neuen Zustand (Sk') bei der entsprechenden Drehzahl (R1, ..., RQ) betrieben werden und wobei das Modifizieren der Drehzahl (R1, ..., RQ) von mindestens einem der Ventilatoren (FIJ) ein Starten der Ventilatoren (FIJ), die sich in dem aktuellen Zustand (Sk) in Ruhe befinden, in Gruppen mit einer Anzahl von Elementen, die nicht größer als
die maximale Anzahl (NMax) ist, umfasst.
10. Verfahren nach Anspruch 9, wobei zwischen dem Start einer Gruppe von Ventilatoren
(FIJ), die sich in dem ausgewählten aktuellen Zustand (Sk) in Ruhe befinden, und dem Start der nachfolgenden Gruppe von Ventilatoren (FIJ), die sich in dem ausgewählten aktuellen Zustand (Sk) in Ruhe befinden, ein Startzeitintervall dazwischengeschaltet ist.
11. Stromkraftwerksanlage, das umfasst:
eine Dampfturbine (3);
einen luftgekühlten Kondensor (8), der mit der Dampfturbine (3) gekoppelt ist, um
Dampf, der von der Dampfturbine (3) kommt, zu empfangen, und der mehrere Ventilatoren
(FIJ) und eine Steuervorrichtung (10) enthält; wobei die Steuervorrichtung (10) konfiguriert
ist:
einen Zustand (Sk, Sk') des Kondensors unter mehreren verfügbaren Zuständen (S1, ..., Sp), die durch einen Satz von Drehzahlwerten (R1, ..., RQ) der Ventilatoren (FIJ) definiert sind, auszuwählen;
eine Anfrage zu empfangen, um einen ausgewählten aktuellen Zustand (Sk) zu modifizieren; einen neuen Zustand (Sk') als Reaktion auf die Anfrage auszuwählen;
die Drehzahl (R1, ..., RQ) von mindestens einem der Ventilatoren (FIJ) von einem ersten Drehzahlwert (R1, R2) auf einen zweiten Drehzahlwert (R2, R1) entsprechend dem gewählten, neuen Zustand (Sk') zu modifizieren;
dadurch gekennzeichnet, dass die Steuervorrichtung (10) ferner konfiguriert ist:
mindestens einen Ventilator (FIJ) zu stoppen;
nach dem Stoppen für die Dauer eines Ruhezeitintervalls (TR) zu warten; und den gestoppten Ventilator (FIJ) mit dem zweiten Drehzahlwert (R2, R1) zu starten.
12. Anlage nach Anspruch 11, wobei die Ventilatoren (FIJ) durch jeweilige elektrische Motoren (MIJ), die von mindestens einem Transformator (24, 25) versorgt werden, betrieben werden,
und wobei das Ruhezeitintervall mit einer Entmagnetisierungszeit der elektrischen
Motoren (MIJ) korreliert ist.
13. Anlage nach Anspruch 12, wobei das Ruhezeitintervall (TR) eine erste Dauer, wenn der erste Drehzahlwert (R1, R2) größer als der zweite Drehzahlwert (R2, R1) ist, und eine zweite Dauer, die nicht größer als die erste Dauer ist, wenn der erste
Drehzahlwert (R1, R2) kleiner als der zweite Drehzahlwert (R2, R1) ist, aufweist.
14. Anlage nach Anspruch 12 oder 13, wobei die Steuervorrichtung (10) ferner konfiguriert
ist:
mehrere Ventilatoren (FIJ) zu stoppen; und
nach dem Ruhezeitintervall (TR) eine Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) von Ventilatoren (FIJ) ist, die ohne Überlastung der Transformatoren (24, 25) gleichzeitig gestartet werden
können, gleichzeitig zu starten.
15. Anlage nach Anspruch 14, wobei die Steuervorrichtung (10) ferner konfiguriert ist,
eine Anzahl von Ventilatoren (FIJ), die nicht größer als die maximale Anzahl (NMax) ist, gleichzeitig zu stoppen und die Betriebsbedingungen der anderen Ventilatoren
(FIJ) gleichzeitig unverändert zu halten.
1. Procédé permettant de commander un condenseur refroidi à l'air d'une installation
de production d'énergie électrique, dans lequel le condenseur (8) comprend une pluralité
de ventilateurs (F
IJ) et un dispositif de commande (10), configuré pour sélectionner un état (S
K, S
K') du condenseur parmi une pluralité d'états valides (S
1, ..., S
P), définis par des ensembles de valeurs de vitesse (R
1, ..., R
Q) des ventilateurs (F
IJ) ;
le procédé comprenant le fait :
de recevoir une demande pour modifier un état actuel sélectionné (SK) ;
de sélectionner un nouvel état (SK') en réponse à la demande ;
de modifier la vitesse (R1, ..., RQ) d'au moins l'un des ventilateurs (FIJ) d'une première valeur de vitesse (R1, R2) à une deuxième valeur de vitesse (R2, R1) en fonction du nouvel état sélectionné (SK') ;
le procédé étant caractérisé en ce que la modification de la vitesse (R1, ..., RQ) comprend le fait :
d'arrêter l'au moins un ventilateur (FIJ) ;
d'attendre un intervalle de temps restant (TR) après l'arrêt ; et
de mettre en marche le ventilateur arrêté (FIJ) à la deuxième valeur de vitesse (R2, R1).
2. Procédé selon la revendication 1, dans lequel les ventilateurs (F
IJ) sont actionnés par des moteurs électriques respectifs (M
IJ), alimentés par au moins un transformateur (24, 25) et comprenant le fait :
de déterminer un nombre maximal (NMAX) de ventilateurs (FIJ) qui peuvent être mis en marche simultanément sans surcharger le transformateur (24,
25).
3. Procédé selon la revendication 2, dans lequel l'intervalle de temps restant est corrélé
à un temps de démagnétisation des moteurs (MIJ).
4. Procédé selon la revendication 2 ou 3, dans lequel l'intervalle de temps restant (TR) a une première durée, si la première valeur de vitesse (R1, R2) est supérieure à la deuxième valeur de vitesse (R2, R1), et une deuxième durée, non supérieure à la première durée, si la première valeur
de vitesse (R1, R2) est inférieure à la deuxième valeur de vitesse (R2, R1).
5. Procédé selon l'une quelconque des revendications 2 à 4, dans lequel la modification
de la vitesse (R
1, ..., R
Q) comprend le fait :
d'arrêter une pluralité de ventilateurs (FIJ) ; et
de mettre en marche simultanément, après l'intervalle de temps restant (TR), un certain nombre de ventilateurs (FIJ) non supérieur au nombre maximal (NMAX) .
6. Procédé selon la revendication 5, dans lequel l'arrêt d'une pluralité de ventilateurs
(FIJ) comprend simultanément le fait d'arrêter un certain nombre de ventilateurs (FIJ) non supérieur au nombre maximal (NMAX), tandis que des conditions d'actionnement des autres ventilateurs (FIJ) sont maintenues inchangées.
7. Procédé selon la revendication 5 ou 6, dans lequel les étapes d'arrêt d'une pluralité
de ventilateurs (FIJ) et de mise en marche simultanément, après l'intervalle de temps restant (TR), d'un certain nombre de ventilateurs (FIJ) non supérieur au nombre maximal (NMAX) sont répétées jusqu'à ce que tous les ventilateurs (FIJ) soient actionnés aux deuxièmes valeurs de vitesse respectives (R2, R1) en fonction du nouvel état (SK').
8. Procédé selon l'une quelconque des revendications 5 à 7, dans lequel les étapes d'arrêt
d'une pluralité de ventilateurs (FIJ) et de mise en marche simultanément, après l'intervalle de temps restant (TR), d'un certain nombre de ventilateurs (FIJ) non supérieur au nombre maximal (NMAX) sont mises en oeuvre de manière essentiellement simultanée.
9. Procédé selon l'une quelconque des revendications 5 à 8, dans lequel au moins certains
des ventilateurs (FIJ) sont au repos dans l'état actuel sélectionné (SK) et sont actionnés à une vitesse respective (R1, R2) dans le nouvel état sélectionné (SK') et où la modification de la vitesse (R1, ..., RQ) d'au moins l'un des ventilateurs (FIJ) comprend le fait de mettre en marche les ventilateurs (FIJ) qui sont au repos dans l'état actuel (SK) dans des groupes ayant un certain nombre d'éléments non supérieur au nombre maximal
(NMAX).
10. Procédé selon la revendication 9, dans lequel un intervalle de temps de mise en marche
est interposé entre la mise en marche d'un groupe de ventilateurs (FIJ) qui sont au repos dans l'état actuel sélectionné (SK) et la mise en marche du groupe suivant de ventilateurs (FIJ) qui sont au repos dans l'état actuel sélectionné (SK).
11. Installation de production d'énergie électrique comprenant :
une turbine à vapeur (3) ;
un condenseur refroidi à l'air (8), couplé à la turbine à vapeur (3), pour recevoir
de la vapeur provenant de la turbine à vapeur (3), et comportant une pluralité de
ventilateurs (FIJ) et un dispositif de commande (10) ;
où le dispositif de commande (10) est configuré :
pour sélectionner un état (SK, SK') du condenseur parmi une pluralité d'états valides (S1, ..., SP), définis par des ensembles de valeurs de vitesse (R1, ..., RQ) des ventilateurs (FIJ) ;
pour recevoir une demande pour modifier un état actuel sélectionné (SK) ;
pour sélectionner un nouvel état (SK') en réponse à la demande ;
pour modifier la vitesse (R1, ..., RQ) d'au moins l'un des ventilateurs (FIJ) d'une première valeur de vitesse (R1, R2) à une deuxième valeur de vitesse (R2, R1) en fonction du nouvel état sélectionné (SK') ;
caractérisée en ce que le dispositif de commande (10) est en outre configuré :
pour arrêter l'au moins un ventilateur (FIJ) ;
pour attendre un intervalle de temps restant (TR) après l'arrêt ; et
pour mettre en marche le ventilateur arrêté (FIJ) à la deuxième valeur de vitesse (R2, R1).
12. Installation selon la revendication 11, dans laquelle les ventilateurs (FIJ) sont actionnés par des moteurs électriques respectifs (MIJ) alimentés par au moins un transformateur (24, 25) et dans laquelle l'intervalle
de temps restant est corrélé à un temps de démagnétisation des moteurs (MIJ) .
13. Installation selon la revendication 12, dans laquelle l'intervalle de temps restant
(TR) a une première durée, si la première valeur de vitesse (R1, R2) est supérieure à la deuxième valeur de vitesse (R2, R1), et une deuxième durée, non supérieure à la première durée, si la première valeur
de vitesse (R1, R2) est inférieure à la deuxième valeur de vitesse (R2, R1).
14. Installation selon la revendication 12 ou 13, dans laquelle le dispositif de commande
(10) est en outre configuré :
pour arrêter une pluralité de ventilateurs (FIJ) ; et
pour mettre en marche simultanément, après l'intervalle de temps restant (TR), un certain nombre de ventilateurs (FIJ) non supérieur au nombre maximal (NMAX) de ventilateurs (FIJ) qui peuvent être mis en marche simultanément sans surcharger le transformateur (24,
25).
15. Installation selon la revendication 14, dans laquelle le dispositif de commande (10)
est en outre configuré pour arrêter simultanément un certain nombre de ventilateurs
(FIJ) non supérieur au nombre maximal (NMAX) et au même temps pour maintenir des conditions d'actionnement inchangées des autres
ventilateurs (FIJ).