NZ717991B2 - Power system - Google Patents
Power system Download PDFInfo
- Publication number
- NZ717991B2 NZ717991B2 NZ717991A NZ71799114A NZ717991B2 NZ 717991 B2 NZ717991 B2 NZ 717991B2 NZ 717991 A NZ717991 A NZ 717991A NZ 71799114 A NZ71799114 A NZ 71799114A NZ 717991 B2 NZ717991 B2 NZ 717991B2
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- NZ
- New Zealand
- Prior art keywords
- power
- motive fluid
- generator
- steam
- power plant
- Prior art date
Links
- 239000012530 fluid Substances 0.000 claims abstract description 119
- 230000001965 increased Effects 0.000 claims abstract description 7
- VLKZOEOYAKHREP-UHFFFAOYSA-N hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 30
- 238000009987 spinning Methods 0.000 claims description 28
- IJDNQMDRQITEOD-UHFFFAOYSA-N butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 claims description 15
- OFBQJSOFQDEBGM-UHFFFAOYSA-N pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims description 15
- 230000001105 regulatory Effects 0.000 claims description 13
- 230000000875 corresponding Effects 0.000 claims description 10
- 239000007789 gas Substances 0.000 claims description 10
- 239000001273 butane Substances 0.000 claims description 9
- 239000008079 hexane Substances 0.000 claims description 9
- 238000002347 injection Methods 0.000 claims description 8
- 239000007924 injection Substances 0.000 claims description 8
- 239000002918 waste heat Substances 0.000 claims description 8
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000001294 propane Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000005338 heat storage Methods 0.000 claims description 4
- 239000012267 brine Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 8
- 230000005611 electricity Effects 0.000 description 8
- 239000007788 liquid Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 230000000153 supplemental Effects 0.000 description 7
- NNPPMTNAJDCUHE-UHFFFAOYSA-N Isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 6
- QWTDNUCVQCZILF-UHFFFAOYSA-N Isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 description 6
- 239000001282 iso-butane Substances 0.000 description 6
- GTJOHISYCKPIMT-UHFFFAOYSA-N 2-Methylundecane Chemical compound CCCCCCCCCC(C)C GTJOHISYCKPIMT-UHFFFAOYSA-N 0.000 description 4
- ZUBZATZOEPUUQF-UHFFFAOYSA-N Isononane Chemical compound CCCCCCC(C)C ZUBZATZOEPUUQF-UHFFFAOYSA-N 0.000 description 4
- 230000003466 anti-cipated Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 206010013975 Dyspnoeas Diseases 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 230000001360 synchronised Effects 0.000 description 2
- 230000001052 transient Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000004301 light adaptation Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000000576 supplementary Effects 0.000 description 1
- 230000001502 supplementation Effects 0.000 description 1
- 230000035899 viability Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
- F01K13/02—Controlling, e.g. stopping or starting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
Abstract
The present invention is directed to a power plant system providing fast ramping up and ramping down for satisfying a load, comprising a turbine module operating in accordance with an organic Rankine cycle or steam power cycle coupled to a generator, the generator supplying power to satisfy the load, a main conduit through which motive fluid vapor heated in the organic Rankine cycle or steam is supplied to the turbine module, and a flow control component operatively connected to the main conduit and a flow control component controller responsive to load conditions for automatically increasing the flow of the motive fluid vapor or steam to the turbine module during ramping up conditions and for automatically limiting the flow of the motive fluid vapor or steam to said turbine module during ramping down conditions. , a main conduit through which motive fluid vapor heated in the organic Rankine cycle or steam is supplied to the turbine module, and a flow control component operatively connected to the main conduit and a flow control component controller responsive to load conditions for automatically increasing the flow of the motive fluid vapor or steam to the turbine module during ramping up conditions and for automatically limiting the flow of the motive fluid vapor or steam to said turbine module during ramping down conditions.
Description
POWER SYSTEM
The present invention relates to the field of power systems. More particularly, the invention
relates to a power system for providing a supplemental reserve of power to a factory (industrial
or commercial) or from a power plant complex such as a geothermal power plant complex.
Many regulations require a manager to specify the power requirements of a factory. If the
transient power requirements of the factory are greater than the specified requirements, the
factory will be prevented to operate at a peak load and the operation of some of the machines
of the factory will have to be terminated.
The present invention relates to methods for ensuring the uninterrupted operation of a factory
equipped with one or more motorized rotating machines by providing a "spinning reserve", i.e. a
supplementary amount of power for use during a variable load, e.g. a peak load, by increasing
the power output of one or more generators that are already connected to the electricity lines
of the factory. The spinning reserve therefore provides extra generating capacity in addition to
the normally sufficient amount of power that the factory receives from an electrical network for
use with respect to a base load.
The base and peak loads of a factory are primarily inductive loads, and these loads require the
supply of active power for powering the machinery and reactive power for sustaining the
electromagnetic field associated with the machinery. The levels of active and reactive power vary
during the course of the day, and reactive power is needed to be supplied to a machine even if it
idle.
Efficient consumption of power in a factory therefore requires the control of both active and
reactive power flow with respect to alternating current (AC) loads. Reactive power flow has been
controlled in prior art systems by switching inductors or capacitor banks, in order to partially
balance the reactive power of the load.
195865NZ CS amended 3 Sept 2020.docx
It would be desirable to provide a simpler reactive power control system that obviates the need
for inductor or capacitor switching devices.
The present invention provides a factory with a custom level of reactive power supplied by a
spinning reserve.
In addition, the present invention provides a power storage control system for adjusting a level
of reactive power that is not based on inductor or capacitor switching devices.
Other advantages of the invention will become apparent as the description proceeds.
The present invention provides a power system for delivering a custom level of electrical power
to an industrial or commercial facility, comprising a local generator connected to a turbine
operating in accordance with an organic or steam Rankine cycle, said local generator having a
capacity at least greater than a maximum anticipated power level needed for the electrical needs
of a local industrial or commercial facility, one or more control devices operatively connected to
said local generator for regulating active and reactive power generated by said generator, a
detector for sensing active voltage induced by said generator, a detector for sensing reactive
voltage produced by said generator, and a controller in electrical communication with said one
or more control devices and with said active and reactive voltage detectors, wherein said
controller directs said one or more control devices to regulate said generator such that the active
power and reactive power generated by said generator are sufficient to satisfy active and reactive
load conditions, respectively, of said local industrial or commercial facility.
It is to be noted that this aspect of the present invention is also applicable to power produced by
geothermal power plants.
The present invention is also directed to a power system for providing a fast acting spinning
reserve, comprising a turbine module of an organic or steam Rankine cycle that is coupled to a
generator, a main conduit through which motive fluid heated in said thermodynamic cycle is
delivered to said turbine module, and a flow control component operatively connected to said
195865NZ CS amended 3 Sept 2020.docx
main conduit for automatically limiting the flow of the motive fluid to said turbine module during
base load conditions and for automatically increasing the flow of the motive fluid to said turbine
module during variable load conditions.
In prior art, geothermal plants have been used substantially only for base loads since flow in a
geothermal production well is usually fairly constant. As the power system of the present
invention provides the spinning reserve needed for transient periods of variable load by means
of the flow control component, e.g. a fast acting bypass valve that diverts motive fluid to a
condenser or to a heat exchanger for producing industrial heat, a lower output of the power
system can be maintained without affecting the flow and operation of the geothermal production
well.
All references, including any patents or patent applications cited or mentioned in this
specification are hereby incorporated by reference. No admission is made that any reference
constitutes prior art. The discussion of the references states what their authors assert, and the
applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It
will be clearly understood that, although a number of prior art publications may be referred to
herein; this reference does not constitute an admission that any of these documents form part
of the common general knowledge in the art, in New Zealand, Australia or in any other country.
It is an object of the invention to provide an improved power plant system that ameliorates some
of the disadvantages and limitations of the known art or at least provide the public with a useful
choice.
In a first aspect, the invention resides in a power plant system providing fast ramping up and
ramping down of power for satisfying a load, comprising: a turbine module operating in
accordance with an organic Rankine cycle or steam power cycle coupled to a generator, said
generator supplying power to satisfy the load, a main conduit through which motive fluid vapor
heated in said organic Rankine cycle or steam is supplied to said turbine module, and a flow
control component operatively connected to said main conduit and a flow control component
195865NZ CS amended 3 Sept 2020.docx
controller responsive to load conditions for automatically increasing the flow of the motive fluid
vapor or steam to said turbine module during ramping up conditions and for automatically
limiting the flow of the motive fluid vapor or steam to said turbine module during ramping down
conditions.
Preferably as disclosed in the first aspect wherein the motive fluid is heated by means of a main
heat exchanger through which high temperature fluid flows.
Preferably as previously disclosed wherein the high temperature fluid is selected from the group
of waste heat gases, geothermal fluid and heat storage fluid.
Preferably as disclosed in the first aspect wherein said organic Rankine cycle utilizes an organic
motive fluid for its motive fluid.
Preferably as disclosed in previous preferment wherein said organic motive fluid for the organic
Rankine cycle is selected from the group propane, butane, pentane, or hexane as its motive fluid.
Preferably as disclosed in the first aspect wherein the flow control component is a turbine
injection valve for controlling the amount of the heated motive fluid supplied to said turbine
module.
Preferably as disclosed in the first aspect wherein the flow control component is a bypass valve
for diverting a portion of the heated motive fluid to a second conduit.
Preferably as disclosed in previous preferment wherein the diverted motive fluid flows via the
second conduit to a secondary heat exchanger wherein fluid used in industrial process heat is
heated.
Preferably as disclosed in previous preferment wherein the diverted motive fluid flows via the
second conduit to a condenser of the organic Rankine cycle.
Preferably as disclosed in the first aspect further comprising a controller in communication with
a control component of the generator, said controller adapted to regulate and control the speed
of the generator.
Preferably as disclosed in the first aspect further comprising a controller in communication with
a control component of the organic Rankine cycle, said controller adapted to regulate the
spinning reserve of said organic Rankine cycle.
195865NZ CS amended 3 Sept 2020.docx
In a second aspect, the invention resides in a power plant system providing fast ramping up and
ramping down of power for satisfying a load, comprising:
a) a turbine module operating in accordance with an organic Rankine cycle or steam power
cycle coupled to a generator, said generator supplying power to satisfy the load;
b) a conduit circuit through which motive fluid heat in said organic Rankine cycle or steam
power cycle circulates;
c) two different flow control components operatively connected to said conduit circuit; and
d) a controller in electrical connection with each of said two different flow control
components and adapted to regulate a spinning reserve of said organic Rankine cycle or
said steam power cycle and being responsive to load conditions,
wherein said controller is configured to cause a response in a first control step of said two
different flow control components so that flow of motive fluid vapor or steam to said turbine
module will be automatically increased during ramping up conditions and to cause a response
in a second control step of said two different flow control components so that flow of motive
fluid vapor or steam to said turbine module will be automatically limited during ramping
down conditions.
Preferably as disclosed in the second aspect wherein a first of the two flow control components
is a bypass valve for diverting a portion of the heated motive fluid from a first conduit of the
conduit circuit to a second conduit thereof, and a second of the two flow control components is
a turbine injection valve for regulating the flow of the motive fluid vapor or steam to the turbine
module.
Preferably as disclosed in previous preferment wherein the controller is operable to, when the
spinning reserve providing excess flow of the heated motive fluid into a main heat exchanger of
the organic Rankine cycle or steam power cycle relative to a flow thereof necessary for use with
respect to a base load is maintained, command closing of the bypass valve which is a turbine
195865NZ CS amended 3 Sept 2020.docx
bypass valve and opening of the turbine injection valve, to ensure that the excess flow will flow
into the turbine module.
Preferably as disclosed in previous preferment wherein the motive fluid prior to flowing to the
turbine module is heated by means of the main heat exchanger through which high temperature
fluid flows.
Preferably as disclosed in previous preferment wherein the high temperature fluid is selected
from the group of waste heat gases, geothermal fluid and heat storage fluid.
Preferably as disclosed in the second aspect wherein said organic Rankine cycle utilizes an organic
motive fluid for its motive fluid.
Preferably as disclosed in previous preferment wherein said organic motive fluid for the organic
Rankine cycle is selected from the group propane, butane, pentane, or hexane as its motive fluid.
Preferably as disclosed in previous preferment wherein the diverted motive fluid flows via the
second conduit to a secondary heat exchanger wherein fluid used in industrial process heat is
heated.
Preferably as disclosed in previous preferment wherein the diverted motive fluid flows via the
second conduit to a condenser of the organic Rankine cycle.
Preferably as disclosed in the second aspect further comprising an additional controller in
electrical connection with a control component of the generator, said additional controller
adapted to regulate and control the speed of the generator in response to the regulated spinning
reserve.
195865NZ CS amended 3 Sept 2020.docx
Preferably as disclosed in the second aspect further comprising a plurality of the turbine modules,
each of said turbine modules being in fluid communication with a corresponding conduit circuit
to which is operatively connected the two different flow control components.
Preferably as disclosed in previous preferment wherein each of the plurality of turbine modules
is coupled to a corresponding generator supplying power to satisfy the load.
Preferably as disclosed in previous preferment wherein a first of the plurality of turbine modules
operates in accordance with an organic Rankine cycle and a second of the plurality of turbine
modules operates in accordance with a steam power cycle.
Preferably as disclosed in previous preferment, wherein the controller is in electrical connection
with a control component of the corresponding generator and is adapted to regulate and control
the speed of the corresponding generator in response to the regulated spinning reserve.
Preferably as disclosed in previous preferment further comprising a net power controller in
communication with the spinning reserve regulating controller which is configured to allocate
net power to each of the turbine modules.
Preferably as disclosed in the second aspect further comprising one or more control devices
operatively connected to the generator for regulating active and reactive power generated by
the generator, wherein the controller is in electrical connection with said one or more control
devices and with said active and reactive voltage detectors, and is operable to command said one
or more control devices to regulate the generator such that the active power and reactive power
generated by the generator are sufficient to satisfy active and reactive load conditions,
respectively, of a local industrial or commercial facility.
195865NZ CS amended 3 Sept 2020.docx
Preferably as disclosed in previous preferment, wherein the active power and reactive power
generated by the generator sufficiently supplement the active power and reactive power,
respectively, supplied by an electric network to satisfy the load conditions of the local industrial
or commercial facility.
Preferably as disclosed in the second aspect, wherein the controller is in further electrical
connection with an active power sensor and with a reactive power sensor for detecting an
instantaneous accumulative electrical load imposed by a local industrial or commercial facility at
a gate region, the controller operable to command one or more control devices in response to
sensed values received from said active and reactive power sensors to regulate the generator
such that the active power and reactive power generated by the generator are sufficient to satisfy
active and reactive load conditions, respectively, of the local industrial or commercial facility.
In the drawings:
- Fig. 1 is a block diagram of a system for controlling a custom level of electrical power supplied
to an industrial or commercial facility, according to one embodiment of the present invention;
- Fig. 2 is a block diagram of a system for controlling a custom level of electrical power supplied
to each of two industrial or commercial facilities;
- Fig. 3 is a block diagram of an exemplary power system for providing supplemental power to an
industrial or commercial facility, according to one embodiment of the invention;
- Fig. 4 is a block diagram of a portion of a power system for providing a supplemental power to
an industrial or commercial facility, according to another embodiment of the invention,'
- Fig.5 is block diagram of a further embodiment of the present invention;
- Fig. 6 is a block diagram of a control system for operation of the embodiment of the invention
described with reference to Fig. 5 operating with spinning reserve; and
195865NZ CS amended 3 Sept 2020.docx
- Fig. 7 is a block diagram showing operation characteristics of the spinning reserve of the
embodiment of the invention described with reference to Figs. 5 and 6.
In the present invention, power devices associated with a local generator that usually has a
capacity equal to or greater than the anticipated variable load/ e.g. a peak load, of an industrial
or commercial facility are employed to supply a custom level of active and reactive power. To
improve the economic viability of the power system, electricity is generated during periods of
variable loads by means of gases or vapors produced in a thermodynamic cycle based on e.g.
waste, geothermal, or stored heat. In addition, the spinning reserve derived from the
thermodynamic cycle can be available to the control system in a short duration of time. Usually,
the thermodynamic cycle includes a turbine driving the local generator operating in accordance
with e.g. an organic Rankine cycle or e.g. a steam Rankine cycle. The organic motive fluid can
comprise propane, butane, e.g. n-butane or isobutane, pentane e.g. n-pentane or isopentane, or
hexane, e.g. n-hexane or isohexane, iso-nonane, iso-dodecane, etc., and cyclo - version of the
above-mentioned non-limiting examples of organic motive fluids previously mentioned.
Fig. 1 is a block diagram of a power system generally designated by numeral 10, according to one
embodiment of the present invention. Load 7 represents the instantaneous accumulative
electrical load imposed by the industrial or commercial facility at a gate region, as detected by
active power sensor 8 and reactive power sensor 9, e.g. a frequency sensor or a power meter.
The electrical requirements of load 7 are partially supplied by electric network or grid 3 via line 4
and partially by local generator 15, which is usually a synchronous generator that supplies
electricity in parallel to electrical network 3 via line 16. Local generator 15 is coupled to a turbine
of thermodynamic cycle 11, which can be a Brayton, Kalina or Rankine cycle. The Rankine cycle
operating generator 15 can be operated in accordance with a closed organic Rankine cycle using
an organic motive fluid, or a closed steam Rankine cycle using water as its motive fluid, which
receives heat from e.g. waste heat from e.g. the factory (industrial or commercial facility) or from
geothermal heat. It will be appreciated, however, that control system 10 is also operational when
generator 15 produces electricity by any other means known to those skilled in the art. While the
195865NZ CS amended 3 Sept 2020.docx
power level supplied by electric network 3 is substantially constant, corresponding to the power
requirements specified by a factory manager, the power supplied by generator 15 is variable.
That is/ generator 15 supplies a first power level during base load conditions and a second power
level during variable load conditions.
The AC electrical power supplied by electric network or grid 3 and by local generator 15 has two
components: an active power component and a reactive power component. The vector sum of
these two components is expressed by the following equationA
S = P + jCt (Equation 1) where S is apparent power, P is active power, Q. is reactive power, and j
is an imaginary unit. When the supplied electric power is in the form of a sinusoidal waveform,
P, Q and S can be expressed as vectors such that-'S2 = P2 + 0.2 (Equation 2)
The power factor, which is the ratio of active power to apparent power, is indicative of the
percentage of reactive loads within load 7 and the corresponding current for the same amount
of apparent power that is transferred. The power factor is generally defined as cosG, where 0 is
the phase angle between the current and voltage. Thus, active power can be expressed by the
following equation: P = S*cos9 (Equation 3)
Usually, the apparent power level is greater during variable load conditions than during base load
conditions. However, the power level could be less during variable load conditions than during
base load conditions. It will also be appreciated that the reactive power level could increase or
decrease when the apparent power level increases from a first load condition to a second load
condition, and likewise the reactive power level could increase or decrease when the apparent
power level decreases from a second load condition to a first load condition. For example, the
active power level could be higher than the reactive power level during normal working hours of
a factory when the machines of e.g. an assembly line are operational, while the reactive power
level could be higher than the active power level after the normal working hours since the
195865NZ CS amended 3 Sept 2020.docx
machines are deactivated and some of the technical staff may stay until later or other times and
operate air conditioners that require a relatively high level of reactive power.
Local generator 15 is adapted to supply each of the required active and reactive power levels for
supplementing the respective power levels supplied by electric network 3, both during base load
conditions and variable load conditions if need be. The capacity of generator 15 is selected such
that it corresponds to the demands of an anticipated peak load. In order to regulate the power
levels, generator 15 is provided with one or more control devices 17, and with detectors 18 and
19 for detecting the active and reactive power (VAR), respectively, induced by the local
generator. Sensors 8 and 9, control devices 17, and detectors 18, 19 are in electric
communication with controller 20, e.g. a PLC controller. After controller 20 receives the detected
load values from sensors 8 and 9, the controller directs each of the control devices 17 to govern
generator 15 in such a way that the required active power level is supplied to load 7 as detected
by sensor 8 and that the induced voltage level as sensed by detector 19 will be sufficient to supply
the required level of reactive power to the load 7 as detected by sensor 9.
Alternatively, the load levels may be manually input to controller 20 in response to a reading of
sensors 8 and 9, whereupon controller 20 directs control devices 17 to govern generator 15 in
such a way that the induced active voltage level as sensed by detector 18 will be sufficient to
supply the required level of active power to load 7 as detected by sensor 8 and that the induced
reactive voltage level as sensed by detector 19 will be sufficient to supply the required level of
reactive power to the load 7 as detected by sensor 9.
The magnetic field of generator 15 may be provided by permanent magnets mounted on a rotor
assembly. The rotor assembly may also comprise a brushless exciter armature and rectifiers. The
permanent magnet generator may supply power to control device 17.
The electromotive force developed by a synchronous generator can be expressed by the
following equation:
195865NZ CS amended 3 Sept 2020.docx
E = K*0*N, (Equation 4) where E is the active voltage normally referred to as the electromotive
force, K is a machine coefficient, (D is the electromagnetic flux, and N is the rotational speed of
the generator rotor.
The voltage level that is induced by a generator is dependent on the change of magnetic flux with
time. The induced active (V) and reactive voltage (VAR) levels can therefore be regulated by
means of a control device 17 in several different ways.
1) Voltage Adjustment- The relation between V and VAR is such that VAR increases as V
decreases. Consequently, a desired level ofVorVAR may be obtained by adjustment of the active
voltage exitation, such as by means of an automatic voltage regulator (AVR).
2) Reactive Voltage Ampere Control- The apparent power is generated such that VAR is
maintained at a set level, as regulated by a VAR controller.
3) Power Factor Control- The generated voltage level is such that it enables a desired power
factor to be maintained.
4) Speed Control - The rotational speed of the generator rotor is controlled in such a way so that
the frequency (f) of the V voltage waveform remains constant.
) Frequency Adjustment- The relation between active power frequency f and active power level
P is a linear function such that P increases as f decreases. Consequently, a desired level of P may
be obtained by adjusting the active power frequency.
Controller 20 is also in electrical communication, e.g. data communication, with flow control
component 22 of thermodynamic cycle 11, in order to permit local generator 15 to supply a
custom level of active and reactive power both during base load conditions and variable load
conditions. Following indication by sensors 8 and 9 that the load conditions of the factory have
changed from a base load to a variable or from a variable load to a base load, as determined by
predetermined rules stored in controller 20, the controller directs component 22 to change its
mode of operation so that generator 15 will generate a sufficient amount of electricity needed
for the given load conditions.
19586SNZ CS amended 3 Sept 2020.docx
Fig. 2 illustrates another embodiment of the invention wherein power system 12 supplies a
custom level of active and reactive power to each of two or more loads in an industrial or
commercial facility, factory or factories. Under normal conditions, generator 15 supplies a
custom level of active and reactive power via line 16, as described hereinabove with respect to
Fig. 1, to the electric grid represented by load 7 of the first factory in the vicinity of which
generator 15 is located. When a controller of a second factory determines that the second factory
requires a greater level of active or reactive power than what is being supplied thereto/ e.g. by
electric network 3, a signal S is transmitted to controller 20 of the first factory to request a
supplemental amount of power, Signal S may be transmitted by any known means, such as
wirelessly or via a data network, and generally includes the level of the requested supplemental
active or reactive power. Controller 20 then directs flow control component 22 of
thermodynamic cycle 11 to change its mode of operation so that generator 15 will generate a
sufficient amount of electricity needed for the load conditions of both the first and second
factories. Local generator 15 is typically coupled to a turbine ofthermodynamic cycle 11, which
can be characterized by a Brayton, Kalina or Rankine cycle. The Rankine cycle operating generator
can be operated in accordance with a closed organic Rankine cycle using an organic motive
fluid, or a steam Rankine cycle using water as its motive fluid/ which receives heat from e.g. waste
heat from e.g. the factory (industrial or commercial facility) or from geothermal heat. The organic
motive fluid can comprise propane, butane, e.g. n-butane or isobutane, pentane e.g. n-pentane
or isopentane, or hexane, e.g. n-hexane or isohexane, iso-nonane, iso-dodecane, etc., and cyclo
- version of the above-mentioned non-limiting examples of organic motive fluids previously
mentioned. It will be appreciated, however, that control system 10 is also operational when
generator 15 produces electricity by any other means known to those skilled in the art. Thus,
generator 15 will deliver a custom level of supplemental active and reactive power to load 7 of
the first factory via line 16 and a custom level of supplemental active and reactive power to the
electric grid represented by load 13 of the second factory via line 23.
Fig. 3 illustrates an exemplary power system 30 for providing a fast acting spinning reserve. Power
system 30 is usually a closed organic Rankine cycle (ORC) power system using an organic motive
195865NZ CS amended 3 Sept 2020.docx
fluid or a closed steam Rankine cycle power system. The organic motive fluid can comprise
propane, butane, e.g. n-butane or isobutane, pentane e.g. n-pentane or isopentane, or hexane,
e.g. n-hexane or isohexane, iso-nonane, iso-dodecane, etc., and cyclo - version of the above-
mentioned non-limiting examples of organic motive fluids previously mentioned. It will also be
appreciated that the spinning reserve can be provided by means of a power system based on a
Brayton or Kalina thermodynamic cycle.
When an organic Rankine cycle power system is used, the organic motive fluid of the organic
Rankine cycle is brought in heat exchanger relation with waste heat gases, such as the exhaust
gases of a gas turbine, a diesel engine, a furnace or heat from geothermal heat. The waste heat
gases are introduced into inlet 41 of heat exchanger 40 and discharged from outlet 48 thereafter,
and the motive fluid flowing through heating coils 45 positioned within heat exchanger 40 is
heated by the waste heat gases, which flow over the heating coils.
Heated motive fluid vapor produced by heating coils 45 is supplied via conduit 32 to organic
turbine module 48, which may comprise more than one pressure stage and expands therein.
Turbine module 48 is coupled to local generator 15. Expanded motive fluid vapor, after power
has been produced by turbine module 48, flows via conduit 34 to recuperator 51. The motive
fluid exits recuperator 51 and is delivered via conduit 35 to condenser 50, which may be air or
water cooled. Cycle pump 53 supplies the condensate via conduit 37 from condenser 50 to
recuperator 51, which heats the condensate, and the heated motive fluid condensate is then
supplied to heat exchanger 40 through conduit 38. It will be appreciated that other power plant
components may be employed as well, according to the requirements of the factory.
Bypass valve 46 is a control valve and is connected to conduit 32. When the factory imposes base
load conditions, controller 20 directs bypass valve 46 to open so that portion of the heated
motive fluid is diverted via conduit 39 to a second heat exchanger 55. Thus, local generator 15
will generate a lower amount of electricity than during variable load conditions. Nevertheless,
controller 20 regulates the active and reactive power levels induced by generator 15 during base
195865NZ CS amended 3 Sept 2020.docx
load conditions to correspond to the needs of the factory. Diverted motive fluid heats a fluid in
heat exchanger 55 for providing industrial heat by means of coils 58. Heat depleted motive fluid
exiting second heat exchanger 55 can be supplied to back to the power cycle through conduit If
the factory does not require industrial heat, valve 59 is closed and the diverted motive fluid will
be directed to condenser 50 via conduit 43.
When the local factory, or alternatively a remote factory, imposes variable load conditions such
as peak load conditions, controller 20 directs bypass valve 46 to close so that the entire amount
of heated motive fluid vapor flowing in conduit 32, or alternatively a large majority thereof, will
be introduced to turbine module 48. Controller 20 also regulates during variable load conditions
the active and reactive power levels induced by generator 15 to supply the load requirements of
the factory.
Alternatively, as shown in Fig. 4, a portion of the heated motive fluid vapor will be diverted by
means of bypass valve 46 to a heat store 66 via conduit 64. Heat store 66 may be in the form of
a body of water that is heated by the heated motive fluid flowing in conduit 32 or other heat
storage means. After thermal energy is accumulated in heat store 66, it can be transferred to
industrial heat processes.
In another embodiment of the invention, a fast acting spinning reserve is provided without use
of a flow control component. In this embodiment, the turbine module is constantly operating at
full efficiency and the local generator generates a power level sufficient for peak load conditions,
such as when industrial heat is not required. When the control system determines that the
factory is imposing base load conditions or variable load conditions having a magnitude of active
or reactive power less than that which is generated by the local generator, the surplus power is
supplied to the electric network. Alternatively, the generator control components regulate the
power output to correspond to the instantaneous load conditions.
195865NZ CS amended 3 Sept 2020.docx
In a further embodiment, particularly relevant to utilization of geothermal heat, designated 70
and described with reference to Fig. 5, an organic Rankine cycle (ORC) power plant can be
operated on brine separated from the geothermal fluid wherein steam condensate supplied from
pre-heaters of combined cycle steam-organic Rankine cycle power plant modules of combined
cycle steam-organic Rankine cycle power plant 75 operating on separated geothermal steam is
added/ using a pump, to the brine supplied to organic Rankine cycle (ORC) power plant 90. In
power plant 70, separated steam operates steam turbines 72A and 72B in combined cycle steam-
organic Rankine cycle power plant modules 75A and 75B which produce power, the expanded,
low pressure steam being supplied to steam condensers/organic motive fluid vaporizers 76A and
76B cooled by pre-heated organic motive fluid and steam condensate and vaporized motive fluid
being produced. The vaporized organic motive fluid produced is supplied to organic vapor
turbines 78A and 78B which produce power via electric generators 80A and SOB present in
combined cycle steam-organic Rankine cycle power plant modules 75A and 75B and the
expanded organic motive fluid vapor is supplied from organic vapor turbines 78A and 78B to
condensers 82A and 82B, which can be air-cooled or water cooled, where organic motive fluid
condensate is produced. Usually condensers 82A and 82B are air-cooled, however can be water
cooled. The organic motive fluid condensate produced is then supplied to pre-heaters 84A and
84B where steam condensate supplied from steam condensers 76A and 76B pre-heats the
organic motive fluid condensate and the pre-heated organic motive fluid condensate is then
supplied to steam condensers/organic motive fluid vaporizers 76A and 76B for cooling the
expanded low pressure steam exiting steam turbines 72A and 72B thus completing the cycle. The
organic motive fluid can comprise butane, e.g. n-butane or isobutane, pentane e.g. n-pentane or
isopentane, or hexane, e.g. n-hexane or isohexane, etc.
In the present embodiment, portion of heat depleted steam condensate exiting pre-heaters 84A
and 84B in line 86 is combined, using pumps 85A and 85B, with separated geothermal liquid or
brine supplied from steam/geothermal liquid or brine separator 71. The combined steam
condensate - separated geothermal liquid or brine in line 87 is supplied to organic Rankine cycle
power plant 90. In organic Rankine cycle power plant 90, although a single level organic Rankine
195865NZ CS amended 3 Sept 2020.docx
cycle power plant can be used, a two level organic Rankine cycle power plant is avantageously
used and combined steam condensate - separated geothermal liquid or'brine in line 87 is supplied
to organic motive fluid vaporizers 92A and 92B in series where organic motive vapor is produced.
Thereafter, heat depleted combined steam condensate - separated geothermal liquid or brine is
supplied in parallel to organic motive fluid pre-heaters 94A and 94B, the further he.at-depleted
combined steam condensate - separated geothermal liquid or brine exiting the pre-heater being
supplied together with other steam condensate and non-condensable gases from steam
condensers/organic motive fluid vaporizers 76A and 76B to injection well 12. In power plant 90,
organic motive vapor produced in organic motive fluid vaporizers 92A and 92B is supplied to
organic vapor turbines 96A and 96B respectively and power is produced by driving generators
98A and 96B usually. Expanded organic motive fluid vapor exiting organic vapor turbine 96A is
supplied via recuperator 99A to organic motive fluid condenser 101A which can be air-cooled or
water cooled/ and the organic motive fluid condensate produced therein is supplied to the
recuperator using cycle 103A where it is heated by the expanded organic motive fluid vapor.
Expanded organic motive fluid vapor exiting organic vapor turbine 96B is supplied to organic
motive fluid condenser 10 IB, which can be air-cooled or water cooled/ and the organic motive
fluid condensate produced therein is supplied to pre-heater 94B using cycle pump. The organic
motive fluid in power plant 90 can comprise butane, e.g. n-butane or isobutane, pentane e.g. n-
pentane or isopentane, or hexane, e.g. n-hexane or isohexane, etc.
In power plant 90, if need be or for a certain reason, one of organic vapor turbines 96A and 96B
can not be operated or idled and be put back into operation when needed or is suitable. In such
a manner, this power plant can be considered as having reserve or additional power available. In
such cases appropriate bypass lines and valves can be used, examples of which are shown in Fig.
(see "dashed - dotted" lines and valves).
Furthermore, by using steam condensate in line 86 to increase the flow of the geothermal brine
or liquid supplied in line 87 to the organic Rankine cycle power plant 90, possible flashing of this
geothermal liquid or brine is avoided. Consequently, the use of a brine supply pump is avoided.
195865NZ CS amended 3 Sept ZOZO.docx
By avoiding the need to use such a brine supply pump, the need to operate the pump under high
temperature conditions (e.g. about 400°F) is avoided.
Here, the organic motive fluid can comprise propane, butane, e.g. n-butane or isobutane,
pentane e.g. n-pentane or isopentane, or hexane, e.g. n-hexane or isohexane, iso-nonane, iso-
dodecane, etc., and cyclo - version of the above-mentioned non-limjting examples of organic
motive fluids previously mentioned.
In addition, with reference to the embodiment described with reference to Fig.5, it could be
advantageous to use a steam cycle power system.
The power produced in accordance with this embodiment and in other embodiments where
geothermal energy is used can be supplied to the power grid located often in an isolated
geographic area, e.g. an island, this power being optionally used to provide power for operating
vehicles by e.g. charge batteries for use in a plug-in hybrid vehicle or in a battery operated electric
vehicle.
Note that, in particular, cyclo - versions of the non-limiting examples of organic motive fluids
mentioned above can be especially advantageous when a specific power plant is operating in an
environment where relatively high ambient temperatures prevail so as to enable the facilitation
of the power plant condenser operation permitting relatively high condensing temperatures to
be used, if advantageous, so that little if any vacuum levels be present in the power plant
condenser.
In a further embodiment of the present invention, a further geothermal spinning reserve system
is described, with reference to Fig. 6, which has relatively fast ramping up and ramping down
characteristics to which reference is now made. In a system similar to the one shown and
described with reference to Fig. 5, by-pass lines 73A and 73B respectively of steam turbines 72A
and 72B; and by -pass lines 79A and 79B of vapor turbines 78A and 78B respectively in power
plant modules 75A and 75B as well as by-pass lines 97A and 97B of vapor turbines 96A and 96B
in organic Rankine power plant 90 are used to by-pass steam and/or organic vapors from steam
195865NZ CS amended 3 Sept 2020.docx
turbines 72A and 72B, organic vapor turbines 78A and 78B and organic vapor turbines 96A and
96B respectively when necessary. Note that while 2 power plant modules 75A and 75B are shown
in Fig. 5, further such power plant modules can be connected in parallel. Thus, in such a manner,
a geothermal power plant can be used as a dispatchable geothermal power plant whenever the
power grid to which it is connected requires additional power. Fig. 6 shows such operation. In
order to meet the ramp up rate a certain amount of spinning reserve must be maintained. This
spinning reserve would be achieved by maintaining excess flow of vaporizers 92A and 92B of each
units containing vapor turbines 96A and 96B respectively. The excess flow would be by-passed
around the turbines directly to condensers 101A and 10 IB respectively. In the case of ramp up
requirement, referring to Fig. 6, turbine injection valves 102A and 102B, shown in Fig. 5, would
respond by opening via control step 202 of control unit 200, and turbine bypass valves 105A and
105B, shown in Fig. 5, would respond by closing to maintain pressure in the vaporizers 92A and
92B respectively.
If further dispatch is required, excess flow of steam condensers/organic motive fluid vaporizers
76A and 76B of units 75A and 75B would be by-passed around organic vapor turbines 78A and
78B directly to condensers 82A and 82B respectively. Here, the ramp up requirement would be
achieved by the respective turbine injection valves 69A and 69B of vapor turbines 78A and 78B,
shown in Fig. 5, responding thereby opening via control step 202 of control unit 200, and turbine
bypass valves 77A and 77B, shown in Fig. 5, would respond by closing to maintain pressure in the
steam condensers/organic motive fluid vaporizers 76A and 76B respectively.
In the case of emergency over frequency, steam turbines bypasses 73A and 73B of units 75A and
75B respectively would be used by opening bypass valves 74A and 74B to quickly reduce
generation and therefore over frequency.
As far as droop speed control is concerned, generators 98A and 98B, as well as generators 80A
and SOB if necessary, maintain a droop frequency through control of the generators speed using
control steps 203 and 205 of control unit 200. E.g. about 4% can be used.
195865NZ CS amended 3 Sept 2020.docx
In addition/ a certain amount of spinning reserve can be maintained by the system described with
reference to Figs. 5 and 6. Fig. 7 shows control scheme 300 showing how such spinning reserve
is maintained during the operation of this system connected to electric grid. E.g. for a system
supplying between 22MW and 38MW, usually about 35MW net power/ a spinning reserve of up
to 3MW can be maintained.
While some embodiments of the invention have been described by way of illustration, it will be
apparent that the invention can be carried into practice with many modifications, variations and
adaptations, and with the use of numerous equivalents or alternative solutions that are within
the scope of persons skilled in the art, without departing from the spirit of the invention or
exceeding the scope of the claims.
195865NZ CS amended 3 Sept 2020.docx
Claims (1)
- CLAIMS 1. l.A power plant system providing fast ramping up and ramping down of power for satisfying a load, comprising: a) a turbine module operating in accordance with an organic Rankine cycle or steam power cycle coupled to a generator, said generator supplying power to satisfy the load; b) a conduit circuit through which motive fluid heat in said organic Rankine cycle or steam power cycle circulates; c) two different flow control components operatively connected to said conduit circuit; and d) a controller in electrical connection with each of said two different flow control components and adapted to regulate a spinning reserve of said organic Rankine cycle or said steam power cycle and being responsive to load conditions, wherein said controller is configured to cause a response in a first control step of said two different flow control components so that flow of motive fluid vapor or steam to said turbine module will be automatically increased during ramping up conditions and to cause a response in a second control step of said two different flow control components so that flow of motive fluid vapor or steam to said turbine module will be automatically limited during ramping down conditions. 2.The power plant system according to claim 1, wherein a first of the two flow control components is a bypass valve for diverting a portion of the heated motive fluid from a first conduit of the conduit circuit to a second conduit thereof, and a second of the two flow control components is a turbine injection valve for regulating the flow of the motive fluid vapor or steam to the turbine module. 19S86SNZ CS amended 3 Sept 2020.docx 3. The power plant system according to claim 2, wherein the controller is operable to, when the spinning reserve providing excess flow of the heated motive fluid into a main heat exchanger of the organic Rankine cycle or steam power cycle relative to a flow thereof necessary for use with respect to a base load is maintained/ command closing of the bypass valve which is a turbine bypass valve and opening of the turbine injection valve, to ensure that the excess flow will flow into the turbine module. 4. The power plant system according to claim 3, wherein the motive fluid prior to flowing to the turbine module is heated by means of the main heat exchanger through which high temperature fluid flows. 5. The power plant system according to claim 4, wherein the high temperature fluid is selected from the group of waste heat gases, geothermal fluid and heat storage fluid. G.The power plant system according to claim 1 wherein said organic Rankine cycle utilizes an organic motive fluid for its motive fluid. 7.The power plant system according to claim 6 wherein said organic motive fluid for the organic Rankine cycle is selected from the group propane, butane, pentane, or hexane as its motive fluid. 8.The power plant system according to claim 2, wherein the diverted motive fluid flows via the second conduit to a secondary heat exchanger wherein fluid used in industrial process heat is heated. 195865NZ CS amended 3 Sept 2020.docx 9.The power plant system according to claim 8, wherein the diverted motive fluid flows via the second conduit to a condenser of the organic Rankine cycle. lO.The power plant system according to claim 1, further comprising an additional controller in electrical connection with a control component of the generator, said additional controller adapted to regulate and control the speed of the generator in response to the regulated spinning reserve. ll.The power plant system according to claim 1, further comprising a plurality of the turbine modules, each of said turbine modules being in fluid communication with a corresponding conduit circuit to which is operatively connected the two different flow control components. 12.The power plant system according to claim 11, wherein each of the plurality of turbine modules is coupled to a corresponding generator supplying power to satisfy the load. 13.The power plant system according to claim 11, wherein a first of the plurality of turbine modules operates in accordance with an organic Rankine cycle and a second of the plurality of turbine modules operates in accordance with a steam power cycle. 14.The power plant system according to claim 12, wherein the controller is in electrical connection with a control component of the corresponding generator and is adapted to regulate and control the speed of the corresponding generator in response to the regulated spinning reserve. 195865NZ CS amended 3 Sept ZOZO.docx IS.The power plant system according to claim 14, further comprising a net power controller in communication with the spinning reserve regulating controller which is configured to allocate net power to each of the turbine modules. IG.The power plant system according to claim 1, further comprising one or more control devices operatively connected to the generator for regulating active and reactive power generated by the generator, wherein the controller is in electrical connection with said one or more control devices and with said active and reactive voltage detectors, and is operable to command said one or more control devices to regulate the generator such that the active power and reactive power generated by the generator are sufficient to satisfy active and reactive load conditions, respectively/ of a local industrial or commercial facility. 17. The power plant system according to claim 16, wherein the active power and reactive power generated by the generator sufficiently supplement the active power and reactive power, respectively, supplied by an electric network to satisfy the load conditions of the local industrial or commercial facility. IS.The power plant system according to claim 1, wherein the controller is in further electrical connection with an active power sensor and with a reactive power sensor for detecting an instantaneous accumulative electrical load imposed by a local industrial or commercial facility at a gate region, the controller operable to command one or more control devices in response to sensed values received from said active and reactive power sensors to regulate the generator such that the active power and reactive power generated by the generator are sufficient to satisfy active and reactive load conditions/ respectively, of the local industrial or commercial facility. 195865NZ CS amended 3 Sept 2020.docx PCT/ra
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/029,599 | 2013-09-17 | ||
US14/029,599 US9618949B2 (en) | 2009-11-19 | 2013-09-17 | Power system |
PCT/IB2014/001823 WO2015040464A2 (en) | 2013-09-17 | 2014-09-15 | Power system |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ717991A NZ717991A (en) | 2020-10-30 |
NZ717991B2 true NZ717991B2 (en) | 2021-02-02 |
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