ES2364206B1 - SYSTEM AND METHOD OF SPEED CONTROL AND REGULATION FOR PELTON TYPE HYDRAULIC GROUPS, AS WELL AS HYDRAULIC WIND POWER STATIONS THAT INCLUDE THIS SYSTEM. - Google Patents

Abstract

System and method of control and speed regulation for pelton type hydraulic groups, as well as hydraulic wind power plants that incorporate this system. # The system can operate in operation mode with zero flow comprising the closing of the flow control elements or injectors ( 6) that make the flow turbined by the hydraulic group (1) null, or in operation in frequency regulation in which a decrease in the frequency of the network or in the derivative of the frequency or in the speed or in the derivative of the speed of the hydraulic group or in a combination of these values with respect to thresholds determines the opening of the flow control elements or injectors (6) quickly for generation and virtually instantaneous supply of power to the network (2).

Description

SYSTEM AND METHOD OF CONTROL AND REGULATION OF SPEED FOR PEL TON TYPE HYDRAULIC GROUPS, AS WELL AS CENTRALS WIND HYDRAULICS THAT INCLUDE THIS SYSTEM

OBJECT OF THE INVENTION

The present invention is applicable to the control and regulation of the speed of Pelton type hydraulic groups, being valid for any type of hydraulic power plant, especially those in weak networks.

It is especially applicable for wind-hydraulic pumping plants, and is aimed at controlling and regulating the speed of turbines, so that the penetration of wind energy in wind-hydraulic systems can be increased so that the supply of Power realized by such systems is more reliable and with better performance.

BACKGROUND OF THE INVENTION

The energy supply from wind groups is not sufficiently reliable due to the nature of the primary energy source.

Therefore, in case of installation of wind groups on islands or in isolated networks, the percentage of wind energy should not be very high so that in case of lack of wind the electricity supply continues. By

3 Or both must have generators of a different nature than wind in reserve.

In the case of hydraulic wind power plants, ideally the

supply with the maximum energy of wind origin, and complement with the

hydraulic turbines, so that supply can be guaranteed in case

of lack of wind. As a result of the entry into operation of the

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Hydraulic group can be the situation that if the conditions of the

wind does not take advantage of all the energy of wind origin, and on the other hand in

In case of lack of wind the electric service could be interrupted due to lack of

generation.

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In case of an energy demand greater than the generation, the

system frequency and therefore the speed of the generators

connected to it descend.

Before an unacceptable decrease in the frequency in the system and for

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avoid its collapse, the usual practice is to use frequency relays

to cause disconnections of some consumers, so that

again the power generated is equal to the one demanded and the frequency

return to its assigned value. In this way the quality of the electrical service is

within the established frequency ranges.

twenty

In the case of hydraulic pumping wind power plants there is the

possibility of storing wind energy in the form of energy

water potential, through pumps. This energy will be later

transformed into electrical energy by means of turbines. Yes however in each

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one of these energy transformations losses occur and the

overall installation performance decreases markedly. Being therefore

the performance in this type of plant is greater the greater the energy of

wind source that goes directly to the network.

3 o

The international patent application W002084116

describes a hydroelectric power plant that uses a plurality of

wind turbines connected to compressed air generators to produce

5 10

air under presure. Said pressurized air is used to drive water through a turbine to produce electrical energy. Water is recycled and the plant includes a reserve pressure air tank to allow the plant to continue operating when wind levels are not sufficient to produce high pressure air. The plant is designed to operate continuously based on wind energy. When the wind ceases and the reserve capacity is exhausted, electricity from a local supplier is used and when an excess of energy is produced it can be supplied to the supplier's network.

DESCRIPTION OF THE INVENTION

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The present invention allows optimizing the operation of Pelton-type hydraulic groups with direct application in increasing wind penetration in wind-hydraulic pumping plants to increase the overall performance of the installation.

2 o

The proposed method allows the operation of the group coupled to the network at an assigned speed and without flow in the turbine, so that the group is prepared to deliver power quickly if required.

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The system consists of a switching regulator and a control module. from speed, a module from

3 o

The switching module allows to select the output signal from the speed regulator or a signal that causes the flow in the turbine to be zero, and the control module selects the operating mode.

The operation of the group according to the following modes:

with East method, consists of the

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• Start Mode The speed regulator modifies the group speed from the zero speed to the assigned speed, for which it will regulate the necessary water flow. Subsequently, the group is connected to the network.

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• Operation mode with Null Flow

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Once the group is connected to the network, the speed control system will close the flow control element or injectors so that the flow is zero, going into the operation mode with zero flow. At this time the group is working coupled to the network.

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The group is prepared to deliver electric power quickly if required by the electric power system. In this situation, the energy supply is carried out by other non-storable energy sources, such as wind groups. However, in case of lack of this non-storable energy (lack of wind) and the consequent lack of electrical power, the frequency of the system will decrease and consequently the speed of the generators. At this time the hydraulic group will enter the frequency regulation mode, delivering power to the network. • Frequency regulation operation mode

3rd

After the decrease in the frequency of the electrical system that is equivalent to a decrease in the speed of the group, since once the group is coupled to the network, the frequency and speed are equal in unit quantities, the speed control system will pass from regulating zero flow to regulating the system frequency. For this and in the absence of electrical power in the system,

it will open the injector or injectors of the turbine and therefore the generator will deliver power in the electrical system so that the frequency of the system will rise accordingly.

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The step to this regulation mode can be done because the frequency of the system falls below a certain value or because the frequency derivative is less than a predetermined value.

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The step can be performed in an identical way using a decrease in speed or in the derivative of the group speed.

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Once the supply of the main energy source is recovered, in this case the wind power will lower the load in the hydraulic group, since the frequency is being regulated. Once the power is sufficiently low, it will be possible to voluntarily switch to the operating mode with zero flow, and leave the group ready for a new switching to the frequency regulation mode.

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The switching of the operating mode from zero flow to operating mode in frequency regulation therefore depends on whether the frequency of the network or that the group speed drops below a predetermined value (it is the same physical phenomenon) or when the derivative of the frequency or the derivative of the speed of the group (same physical phenomenon) is lower than a previously programmed value. In this way, the control system anticipates the problem of an excessive decrease in the frequency that the shedding relay action can produce.

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BRIEF DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the features of the invention,

In accordance with a preferred example of practical realization thereof, a set of drawings is attached as an integral part of said description, where, as an illustration and not limitation, the following has been represented:

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Figure 1.- Shows a possible configuration of the control and speed regulation system in Pelton type hydraulic units.

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Figure 2. Shows a temporal representation of the evolution of certain variables of a hydraulic group using the proposed method of operation, based on the commutation by lowering the frequency or the speed of the group below a preset value.

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Figure 3. Wind-hydraulic sample. a schematic representation from a central

PREFERRED EMBODIMENT OF THE INVENTION

2nd

A preferred embodiment of the object of the invention is described below.

25 3rd

Figure 1 shows a possible configuration of the speed control and regulation system for hydraulic groups (1) Pelton type associated with a generator (20) to supply electric power to the network (2) where it is represented: -a speed sensor (3) that provides the signal corresponding to the speed of the hydraulic group (1), -a voltage transformer (5) and a current transformer (4) that provide voltage and intensity signals from which the power is calculated power supply supplied by the generator (20) to the network (2), -a flow control element or injectors (6) that regulate the flow of turbined water by the hydraulic group (1),

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a speed regulator (7) that receives the signal from the speed sensor (3), the voltage and intensity signals with which it calculates the power of the generator (20), and that sends a regulation signal to the control elements of flow or injectors (6) to control the flow of turbined water by the hydraulic group (1),

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a switching module (8) associated with the output of the speed regulator (7) that receives the regulation signal from the speed regulator (7) and a fixed zero-flow signal (9) and has a switch (10) that select one of said signals to be sent to the flow control element or injectors (6),

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a control module (11) of operating modes incorporating a flip-flop (12) that selects between a null flow operating mode or a speed regulation operating mode, depending on whether some of the signals of the following variables : network frequency, derived from the network frequency, angular velocity or derived from angular velocity, or a combination thereof, is lower than established thresholds, with the flip-flop (12) related in its output with the module of switching (8) to act on the switch (10) defining one or the other mode of operation.

The control module (11) is related to a connection detector

(13) which determines whether the hydraulic group (1) is connected to the network (2).

The control module (11) incorporates a first manual or automatic push button (14) that allows the selection of the operating mode with zero flow when the connection detector (13) indicates that the generator (20) is connected to the network (2) ), as well as having a first activation module

(15) of the operation mode with zero flow that receives signal from the first

button (14) and the connection detector (13) and which is connected at its output 3 O to the flip-flop (12).

The control module (11) incorporates a second manual button (16) or

automatic and signal comparison modules (17) of: frequency,

frequency derivative, velocity and / or velocity derivative with thresholds

established, which are associated with the voltage transformer (5) of which

5

receives signals corresponding to these variables and that are connected to a

second activation module (18) of operation control mode of

speed regulation connected at its exit to the flip flop (12).

Figure 2 shows the system variables:

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speed (21) of the hydraulic group (1), the terminal voltage (22) of the generator

(20), the flow rate (23) in the hydraulic group (1) and the electrical power (24) of the

generator (20), and in order the different modes of operation at

length of time evolution: start (31), zero flow (32) and regulation of

frequency (33).

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Also within the time evolution have been noted, the point

group start (26), the synchronization point with the network (27), the point

of closing of the injectors (28) corresponding to the step to the mode of

operation with zero flow and finally the waypoint to the regulation mode

2nd

frequency (29) caused by a decrease in group speed (21)

below a speed threshold (30).

Figure 3 shows a scheme of the wind power plant

Hydraulics that supply electric power to the network comprising:

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-a wind farm (40) that provides electric power to a power line

power (41) connected to the network (2),

-a hydraulic group (1) of the Pelton type on which the water acts

stored in height that provides power to the power line

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(41),

-a central pumping (50) that drives water for your

storage in height and that feeds on the power line (41).

The wind-power plant incorporates the speed control and regulation system for hydraulic groups (1) described above.

The wind-hydroelectric power plant operates in accordance with a method of control and regulation of the supply of electric power to the network, which comprises the simultaneous or alternative supply of electric power by a wind farm (40) and / or a hydraulic group ( 1), in which when the power supplied by the wind farm (40) is sufficient to meet the demand of the network, the hydraulic group (1) operates in operation mode with zero flow comprising the closing of the control elements of flow (6) that turbinate the hydraulic group (1).

On the other hand when there is a decrease in the frequency of the network or in the derivative of the frequency or in the speed or in the derivative of the speed of the hydraulic group (1) or in a combination of these values with respect to thresholds, The flow control elements (6) are opened quickly for generation and practically instantaneous supply of power to the network (2) operating in frequency regulation operation mode.

Claims (7)

1.-Speed control and regulation system for hydraulic groups (1) Pelton type associated with a generator (20) to supply electrical power to the network (2) comprising:

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a speed sensor (3) that facilitates the signal corresponding to the speed of the hydraulic group (1),

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a voltage transformer (5) and a current transformer (4) that provide voltage and current signals from which the electrical power supplied by the generator (20) to the grid (2) is calculated,

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a flow control element (6) or injectors that project the water flow on the hydraulic group (1), characterized in that it additionally comprises:

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a speed regulator (7) that receives the signal from the speed sensor (3), the voltage and intensity signals with which it calculates the power of the generator (20), and that sends a signal of the projected flow, and that sends a regulation signal to the flow control elements (6) to control the flow turbined by the hydraulic group (1),

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a switching module (8) associated with the output of the speed regulator (7) that receives the regulation signal from the speed regulator (7) and a fixed signal of zero flow (9) and has a switch (10) that select one of said signals to be sent to the flow control element (6),

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an operating mode control module (11) incorporating a flip-flop (12) that selects between a null flow mode of operation of the hydraulic group (1) coupled to the network at an assigned speed and without flow circulating through it ( 1) in such a way that power is not supplied to the network by the hydraulic group (1), or a speed regulation mode of operation such that the energy is supplied to the network by the hydraulic group (1) , depending on whether some of the signals of the following variables: network frequency, derived from the network frequency, angular velocity or derived from angular velocity, or a combination thereof, is lower than established thresholds, being the flip-flop (12) related at its output with the switching module (8) to act on the switch (10) defining one or another mode of operation.

2. Speed control and regulation system for Pelton type hydraulic groups according to claim 1 characterized in that the control module (11) is related to a connection detector (13) that determines if the hydraulic group (1) is connected to the network (2). 3.-Speed control and regulation system for Pelton type hydraulic groups according to claim 2 characterized in that the control module (11) incorporates a first manual or automatic push button (14) that allows the selection of the operating mode with flow null when the connection detector (13) indicates that the hydraulic group (1) is connected to the network (2), as well as having a first activation module (15) of the operation mode with zero flow that receives signal from the first button (14) and the connection detector (13) and which is connected at its outlet to the flip-flop (12). 4.-Speed control and regulation system for Pelton type hydraulic groups according to claim 3 characterized in that the control module (11) incorporates a second manual or automatic push button (16) and signal comparison modules (17) of: frequency, derived from frequency, speed and / or derived from speed with the established thresholds, which are associated to the voltage transformer (5) from which it receives signals corresponding to these variables and which are connected to a second activation module ( 18) of speed control operation control mode connected at its output to the flip-flop (12). 5.-Speed control and regulation method for Pelton type hydraulic units characterized in that it comprises the phases of:

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start-up operation, which comprises the regulation at start-up of the group speed from the zero speed to an assigned speed and connection of the hydraulic group to the network, -operation with zero flow comprising the closing of the flow control elements that make the flow turbined by the hydraulic group zero, -operation in frequency regulation in which a decrease in the frequency of the network or in the derivative of the frequency or in the speed or in the derivative of the speed of the hydraulic group or in A combination of these values with respect to thresholds determines the opening of the flow control elements quickly for practically instantaneous generation and supply of power to the network.

6.-Wind-hydroelectric power station that supplies electric power to the network (2) comprising:

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a wind farm (40) that provides electrical power to a power line (41) connected to the grid (2),

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a hydraulic group (1) of the Pelton type on which the water stored in height acts that provides electric power to the power line (41),

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a pumping unit (50) that drives water for its storage in height and that feeds on the power line (41), characterized in that it incorporates the speed control and regulation system for hydraulic groups (1) described in any one of claims 1 to 4.

7. Method of controlling and regulating the supply of electric power to the network in the wind-hydraulic power plant described in claim 6, which comprises the simultaneous or alternative supply of electric power by a wind farm (40) and / or of a hydraulic group (1), characterized in that: when the power supplied by the wind farm (40) is sufficient to meet the demand of the network (2), the hydraulic group (1) operates coupled to the network at an assigned speed and without flow circulating through it (1), in a mode of operation with zero flow comprising the closing of the flow control elements (6) that project water to the hydraulic group (1), as well as when there is a decrease in the frequency of the network or in the derivative of the frequency or in the speed or in the derivative of the speed of the hydraulic group (1) or in a combination of these values with respect to thresholds, It produces the opening of the flow control elements (6) quickly for generation and practically instantaneous supply of power to the network (2) operating in frequency regulation operation mode. eleven

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