ES2325902B2 - TEST BANK OF ELECTRICAL, GENERATOR OR CONSUMER EQUIPMENT, AGAINST VOLTAGE HOLES. - Google Patents

Abstract

Electrical equipment test bench, generators or consumers, facing voltage dips.

Electrical equipment test bench against voltage gaps comprising a programmable tension profile consisting of:

(a) a power module that integrates a synchronous rotary electric machine of (5) that has a specific connection automation (14), composed of at less:

- four elements of maneuver (18, 19, 20 and 21) low or medium voltage and

- an integrated system for limiting switching current, in turn composed of at least:

- two impedances (22 and 23) associated with a system for voltage adaptation (11) composed of two equal three-phase transformers (15, 16), with a level of adaptive rated voltage via sockets;

where said synchronous rotary electrical module (5) is driven through a synchronous drive module (12) that keeps the speed of rotation constant; Y

(b) a control system (9) over the system of power (5) described above consisting of a programmable device that sends connection and disconnection orders to the connection automation (14) and which controls the voltage of module excitation (5) depending on the evolution setpoint Temporary desired for tension.

Description

Electrical equipment test bench, generators or consumers, facing voltage dips.

Object of the invention

The present invention aims to present a programmable temporal profile voltage gap generator, composed of electromagnetic and electromechanical devices that is able to reproduce the temporal evolution that the wave would adopt voltage at the connection terminals of a device, generator or receiver, connected to a high voltage power network, during the circumstances corresponding to "voltage dips", including the interval in which the fault is maintained, and the interval recovery after clearing it, as it has been defined above. Said device provides a testing and approval tool for generators / receivers (especially relevant in the case of wind turbines) connected to the distribution and / or transport network, in front of "gaps in tension "with different profiles of temporal evolution adaptable to the "pattern" established by the applicable regulations in each case and without the need to cause "real" failures in the net.

Field of the Invention

The invention falls within the technical sector of the quality and reliability of the electric service, more specifically regarding the evaluation systems of the response of electric generators and receivers against disturbances, mainly in the face of voltage dips.

Background of the invention

It is understood by "tension gap" in a point of the electricity grid, the permanence of the effective value of the mains voltage below 80% of its assigned value, during a period less than or equal to one second. Usually these gaps are caused by the influence on the point in question, of a short circuit or "fault" at some other point in the network, more or  less distant, which is cleared correctly by the performance of the protections The period to consider includes the time in which failure and recovery time has been maintained, after that the protections act.

One of the biggest current concerns of Electric system operator, to ensure its reliability, is know the capacity of the new generation systems electricity with renewable energy and, in particular, wind farms wind turbines, to stay connected during severe voltage dips caused by network failures, and thus be able to contribute to the recovery of the system once the fault is cleared:

Also the current legislation encourages through a specific supplement (5% of the rate), at wind installations that can contribute to the continuity of supply against voltage dips, and install the equipment necessary regulation for it. (Royal Decree 436/2004, BOE No. 75, March 27, 2004).

It is therefore of great interest to develop a "programmable profile voltage gap generator" equipment so that, connected to the electrical terminals of the system generation, allow to reproduce the conditions to which it looks submitted during defective situations in the network and thus be able to analyze your ability to contribute to the recovery of system once the fault is cleared.

Voltage gap generators currently. Existing, are used in Quality of Service electrical and its design is oriented to the accreditation of behavior of receiving equipment, such as drives industrial and all kinds of semiconductor devices, compared to the appearance of gaps in the supply voltage, according to different international regulations (SEMI F47, ITIC, CBEMA or IEC6100-4-11).

It should also take into account a series of patents and prototypes related to the invention. For example, US6285169 entitled "SAG GENERATOR WITH SWITCH MODE IMPEDANCE "and US Patent 20030230937" SAG GENERATOR WITH PLURALITY OF SWITCH TECHNOLOGIES ", correspond to teams of generation of holes using electronic equipment whose maximum achievable power is limited to a value less than 100 kW, for Be able to generate the wave correctly. This limit is clearly less than necessary for wind turbine testing or large receivers (2-3MW), application to which it is intended Mainly the invention.

The equipment referred to in both the patent WO0060430 "Non rotating portable voltage sag generator", as in the Collins ER article, Morgan RL "A Three-phase Sag Generator for Testing Industrial Equipment "(IEEE Transactions on Power Delivery, Vol. 11, No. 1. January 1996), as well as in the JL article. Rodriguez "Wind turbine response measurement procedure before voltage gaps with the mobile unit ULISES "(Energy Magazine, No. 191. Mar / April 2006), do not have this power limitation to be composed of electromagnetic devices, therefore it they are closer to the object of the invention. In the first two you they use auto-transformers while in the Lastly mentioned, a synchronous generator is used. These teams could manipulate power values of the order of required by wind or large generation systems receivers (2-3 MW), although they pose different problems associated with scaling, due to the use of electronic power. However, the temporal profile of the tension gap that is generated with such equipment differs from that required by wind generation systems, in relation to evolution Temporary tension during recovery (P.0.12.3 BOE 254 of October 24, 2006). While it must present a profile with a sharp initial fall, followed by a progressive recovery in ramp shape, the aforementioned gap generators are only capable of causing sudden falls and tension recovery.

Description of the invention

The present invention is a gap generator Tensile programmable temporal profile, consisting of electromagnetic and electromechanical devices that is capable of reproduce the temporal evolution that the voltage wave would adopt in the connection terminals of a device, generator or receiver, connected to a high voltage electrical network, during circumstances corresponding to "voltage dips", including the interval in which the fault is maintained, and the interval recovery after clearing it, as it has been defined above. Said device provides a testing and approval tool for generators / receivers (especially relevant in the case of wind turbines) connected to the distribution and / or transport network, in front of "gaps in tension "with different profiles of temporal evolution adaptable to the "pattern" established by the applicable regulations in each case and without the need to cause "real" failures in the net. The generator object of the invention comprises at least the following subsystems:

(i) A first power system MSPP (Synchronous Rotary Electric Machine with Programmable Profile) which, in turn, comprises at least:

(to)

a synchronous rotary electric machine with an excitation system static, where said static excitation system is composed by:

-

a excitation transformer,

-

a controlled rectifier, and

-

a voltage transformer for measuring the output voltage of the synchronous rotary electric machine.

(ii) A second switching system CF (Source Switch) configured to switch the voltage provided by the network and the voltage provided by the synchronous rotary electric machine, and consisting of four operating elements contactors or circuit breakers and two impedances.

(iii) A third phase selection system SF (Phase Selector), which allows to select in each of the three phases of the three-phase system, independently:

-

yes the power is through the network voltage, or

-

yes the power is through the output of the switch module phases

So that gaps can be made single phase, two phase or three phase.

(iv) A fourth REG (Regulation) control system that controls, on the one hand, the voltage of the synchronous rotary electric machine through the feeding of the rotary winding with the controlled rectifier, and on the other hand the position of the contactors of the CF switching module

(v) A fifth synchronous drive system AS (Synchronous Drive), consisting of a second synchronous rotary electric machine, with its excitation system comprising:

-

a excitation transformer, and

-

a controlled rectifier, whose axis is connected to the axis of the First synchronous rotary electric system machine. MSPP and It aims to maintain the speed of synchronism, so that the voltage generated is the same frequency as the net.

(vi) A sixth system of regulation of power factor RFP (Regulation of the power factor) that controls the excitation voltage of the synchronous rotary electric machine of the synchronous drive module and aims to maintain the input power factor of the equipment at a reference value, so that there are no reactive power fluctuations in the network while testing.

(vii) A seventh ADT (Voltage Adapter) voltage adaptation system consisting of two identical transformers with multiple voltage ratios, to adapt the grid voltage to the voltage of the synchronous rotary electric machines used, circuit breakers input and output, as well as current and voltage measurement transformers.

Thanks to the system so described, a profile of the amplitude evolution of the "hollow" voltage Adjustable to the recovery ramps of a real voltage gap. On the other hand, by not using electronic converters for real hoist the continuous regulation of the voltage in the circuit power, does not introduce any distortion in the voltage waves and of current, during the hollow.

The system provides continuous regulation of the slopes of each tension ramp during the period of recovery, directly modifying the excitation current of a synchronous rotary electric machine, which provides waves sinusoids of adjustable amplitude. In addition, it maintains the frequency of the tension during the gap, without using speed regulators, the network itself being the one that sets the generator frequency of gaps when using the synchronous drive.

At the point of the network where the generator gaps are connected, as the power factor is adjustable, it you can get only active power flow, so the current is reduced than the realization of a real gap would inject into the network. Therefore the network will not have any disturbance due to the fact that it is conducting tests, with the consequent advantage for nearby elements.

In a second aspect of the present invention the operation procedure of the system object of the invention It comprises at least the following stages:

(i) A first stage of adaptation of the ADT module transformer voltage according to the voltage of the network where the test is to be carried out and the phases are selected that will be affected by the gap in the SF module.

(ii) A second stage of network connection to the input terminals of the gap generator and the terminals of Team exit to the team that wants to be tested.

(iii) A third stage where the Gap generator input circuit breaker, subsequently starting the synchronous rotary electric machine of the drive module through its maneuvering element.

(iv) A fourth stage where you feed voltage assigned to the equipment under test for which they will be closed the corresponding circuit breakers.

(v) A fifth stage where the module is started synchronous drive, feeding the electric machine rotary synchronous to assigned voltage, using the element of corresponding maneuver. The machine start method can be asynchronous start, by means of a speed variator. Subsequently, the rotary electric machine is synchronized synchronous power module MSPP to the output bars of the CF module through impedance. The REG regulation module perform this maneuver by measuring the tension of the machine and the bars through two voltage transformers and when detects electrical synchronism conditions sends closing order to the switch.

(vi) A sixth stage where once the machine is coupled the regulation module adjusts the voltage of the same to the start value of the hole. This maneuver is programmed in the regulation module REG.

(vii) A seventh stage where the module of REG regulation sends orders to the CF switching module, so that the power of the output transformer, which was carried out at through the input transformer with assigned voltage become Powered by the synchronous rotary electric machine voltage of the MSPP power module.

(viii) A final stage where the system of regulation controls the controlled rectifier so that the synchronous machine voltage and therefore the equipment output it is the desired one, previously programmed in the regulation system, faithfully reproducing the desired profile for evolution Temporary "hollow tension".

Brief description of the figures

Then it goes on to describe very brief a series of drawings that help to better understand the invention and that expressly relate to an embodiment of said invention presented as a non-limiting example of is.

Figure 1.- Represents a general scheme of set of the invention, where the components are represented fundamentals that constitute its structure.

Figure 2.- Represents a detailed scheme of the REG module for dynamic regulation of the generated voltage profile; by the synchronous rotary electric machine of the MSPP module.

Figure 3.- Shows an example of the profile of the temporal evolution of the tension of a gap for approval of wind turbines.

Figure 4.- Shows a hole made in the laboratory for a prototype of the hollow generator object of the present patent.

Preferred Embodiment of the Invention

An embodiment of the equipment is described below, which can serve as an example of application, while allowing to describe what can be done with the invention. As can be seen in Figure 1, the input terminals 2 must be connected, in direct sequence, to the three-phase supply line 1 . The output terminals 3 must be connected, in direct sequence, to the terminals of the test equipment 4 . The system object of the invention comprises the following subsystems or modules:

(a) Module MSPP (Synchronous Rotary Electric Machine Programmable Profile) referenced as 5 , which is the power equipment that generates a variable effective value voltage, comprising:

-

a synchronous rotary electric machine 6 ,

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excitation transformer 7,

-

a controlled rectifier 8, and

-

a voltage transformer 10.

(b) ADT Module (Voltage Adapter) referenced as 11, which is the equipment for adapting voltage levels, comprising at least:

-

two transformers, one reducer 15 and another elevator 16 with levels of adaptable voltage through sockets.

(c) CF Module (Source Switch) referenced as 14, comprising at least:

-

a exit 47, and

-

two power inputs, where a first input 33 comes from the ADT module 11, and a second input 32 from the MSPP module 5; Where, in addition, this CF 14 module switches between the two inputs (32,33) the output being responsible for feeding the transformer elevator 16 that will subsequently feed the tested equipment Four.

(d) SF Module (Phase Selector) 39 comprising at least:

-

three single-phase independent medium voltage switches with manual or motorized drive, which allows the feeding of each of the phases that the output transformer 16, from the network 46 or from output 47 of source switch 14, allowing to generate single-phase, two-phase and three-phase holes, in function of the position of the three selectors.

(e) AS module (Synchronous Drive) 12, consisting of a synchronous rotary electric machine 34, with its excitation system formed by an excitation transformer 13 and a controlled rectifier 25, whose axis 35 is connected to the machine axis 36 of the power system 6 and aims to maintain the synchronism speed, so that the voltage generated is the same frequency as the network.

(f) RFP Module (Power Factor Regulator) 24, which controls the excitation voltage of the synchronous rotary electric machine 34 of the synchronous drive module 12 and aims to maintain the input power factor of the equipment at a reference value , so that it can be selected as a slogan to have a power factor at the equipment input (2) equal to the unit, and it is achieved that only active power is exchanged with the network (1) during the realization of the hole, by what the current injected into the network (1) is similar to the current in permanent operation of the equipment to be tested (4) assuming a great advantage from the point of view of the network users that will not be disturbed by the testing

(g) REG (Regulation) module 9 for dynamic regulation of the voltage profile generated by the synchronous rotary electric machine 6, where the voltage setpoint signal 41 is programmable and can perform multiple types of gaps, and comprises

-

a voltage measurement adapter 40 that converts the voltage of the generator from the measuring transformers (10)

Said three-phase and alternating voltage is converted. in a continuous value proportional to its effective value. This value is compared to the voltage setpoint 41, and the signal resulting 42 passes through a PID type regulator 43 that generates an output signal 44. This signal is converted through a control card 45, in pulses to fire the semiconductors of the controlled bridge 8. The power output of the bridge controls The field winding voltage of the rotary electric machine synchronous 6, and thus the voltage in terminals thereof. He REG module can be performed using a PLC, a PC or any control equipment

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The assigned voltage of synchronous machines Rotary electric (6.34) will be chosen among the values standardized (6.6kV; 6kV; 4.16kV; 3.3kV, 690V, 400V; etc.) in team power function.

Modifying the field winding current of the synchronous rotary electric machine (6) through the controlled rectifier (8), the voltage amplitude is modified resulting without modifying either the frequency or the waveform sinusoidal.

The expression that establishes the relationship between output voltage U_ {e} and current in the field winding I_ {f}, is:

one

Where I is the comment in the armature of the synchronous rotary electric machine and X is the internal reactance of the same.

The output of the REG module (9) is connected to the controlled rectifier (8) and, through it, regulates the voltage of excitation of the synchronous rotary electric machine (6).

In this module, the temporal evolution of the desired profile of the setpoint signal (41) that must follow the effective value of the voltage applied to the equipment to be tested is programmed from a PC or PLC controller. This block (41) allows to program in situ the desired voltage profile for the signal. Subsequently, the voltage regulation is carried out, through the PID regulator (43) comparing the setpoint (41) with the measurement of the voltage (40) of the generator (6).

The sequential connection of the invention to equipment to be tested, is established through the CF module. Is about a set of 4 contactors or circuit breakers (18, 19, 20 and 21) fast acting, to enable the safe maneuver of connection and disconnection of the group during the test, and its control circuitry They connect as follows:

- The group of contactors or switches called automatic (20) and (21), the network, the team to test.

- The synchronous drive must be started, used any method: asynchronous start, drive speed, etc., causing both rotary electric machines  synchronous (6) and (34) rotate at synchronism speed.

- The synchronous rotary electric machine of Programmable profile is synchronized with the network by closing the contactor or switch (18) through the impedance (22), the contactor or circuit breaker (19) open.

- Once the maneuver of synchronization decreases the excitation intensity of the synchronous rotary electric machine (6) until you have in your terminals the desired tension at the bottom of the hole.

The sequence of action of these contactors for the test start and switching maneuver, it is collected in The following table:

2

The tension of the connection line of the equipment that is intended to be tested with this invention, is usually between 10 and 30kV, while the voltage assigned of synchronous rotary electric machines, which establish the temporal profile of the tension during the test, it is different (6.6kV, 6kV; 3.3kV; 690V; 400V etc .; as appropriate). He ADT module (11) has two identical transformers, one in the entrance (15) and another at exit (16), to adapt these levels tensile.

The higher voltage side of the transformer of the input (15) must be connected to the terminals of the line connection, and the lower voltage side must be connected, simultaneously, to the input terminals of the MSPP module (5) and the terminals (33) of the CF module (14). The side of greatest tension of the output transformer (16) must be connected to the output terminals to the equipment to be tested (3), and the side of lower voltage at the output terminals of the CF module (14).

Therefore, the void generator of the present invention allows testing of generators or receivers, being able to be the power flow from the gap generator to the network or from the network to the gap generator respectively. In the case of perform generator tests the synchronous machine 34 works as generator and synchronous machine 6 works as motor. At If the equipment to be tested 4 is a receiver, the synchronous machine 34 works as a motor and the synchronous machine 6 works as generator.

In the following, and by way of example, it is described the method of use and operation of the invention presented to reproduce the tension profile of the figure 3 on the terminals of a wind turbine (equipment to be tested) connected to a line.

1. Preparation of the gap generating equipment for tension

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Module CF. This module is kept deactivated with all contactors or circuit breakers (18, 19, 20 and 21) in open position. This module will make the necessary connections to execute the maneuver.

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Module SF. Switch positions must be selected depending on the type of hole you want to make; three phase, Biphasic or single phase.

-

Module ADT prepares the connection of both transformers for voltage of the equipment to be tested, for which the shots in the input and output transformers (15) and (16).

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Module REG (Fig 2). The defined temporal tension profile is programmed (see  figure 3) to adjust the reference (41).

-

Subsequently the contactors (19) and (21) being fed the equipment object of test (4) at assigned voltage and frequency. This state corresponds to the state (1) of the sequence of the state of the contactors

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2. Execution of the trial

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Module CF. Starting from the state of sequence 1 of the table, which corresponds to the test equipment fed from the network, the synchronous rotary electric machine (6) must be synchronized to through the impedance (22) closing the contactors (18). In this moment the state of the contactors corresponds to state "2" of the table.

-

In this time the REG module adjusts the tension in the machine's berets (6) at the start value of the hole (20% in this case), for subsequently modify the status of the contactors from the state "2" to state "5", going through the states "3" and "4".

-

He regulation module (9) once the transition begins it maintains the tension in the berets of the machine (6) according to the setpoint (41). In In this case, the hole corresponds to the one shown in Figure 3. During the period "1-2" (500 ms), the regulation device keeps the voltage at 20% of the value rated generator voltage. During the period "2-3" (500 ms), the REG module (8) does Tracking the voltage recovery ramp up to 80% of the assigned value of the voltage. During the period "3-4" (14 s), the REG module (8) makes monitoring of a new tension recovery ramp, from the 80% to 95% of the assigned value. At this point, the test following the usual protocol of disconnection of the wind turbine

Claims (6)

1. Test bench for electrical equipment, generators or consumers, against voltage dips, which allows to obtain a programmable voltage profile, characterized in that it comprises: (a) a first rotary electric machine synchronous (6) responsible for generating an effective value voltage variable and excited by a first excitation transformer (7) and a first controlled rectifier (8); (b) a second rotary electric machine synchronous (34) coupled to the network (1), whose axis (35) is connected to the shaft (36) of the first synchronous rotary electric machine (6) to maintain the speed of synchronism; (c) a source switch (14), consisting of at least:

-

four contactors (18, 19, 20 and 21) and

-

a integrated switching current limitation system, composed of at least:

-

two impedances (22 and 23);

said source switch having (14) from:

-

a output (47) responsible for feeding the equipment under test (4), Y

-

two power inputs, a first input (33) from the network (1) and a second input (32) from the first machine synchronous rotary electric (6);

the source switch being configured (14) to switch between the two inputs (32.33); Y (d) a control system (9) consisting of a programmable device responsible for controlling the position of contactors (18, 19, 20 and 21) of the source switch (14) and of control the excitation voltage of the first electric machine synchronous rotary (6) depending on the evolution setpoint Temporary desired for tension. 2. Test bench according to claim 1, characterized in that it further comprises a phase selection module (39) composed of three single-phase switches with independent control, which allows the feeding of each of the phases of the test equipment (4) from the network (1) or from the output (47) of the source switch (14), allowing generating single-phase, two-phase and three-phase gaps depending on the position of said three switches. 3. Test bench according to any one of claims 1 to 2, characterized in that it also includes a power factor regulator (24) responsible for controlling the excitation voltage of the second synchronous rotary electric machine (34) to maintain the factor of input power at a reference value. 4. Test bench according to any one of claims 1 to 3, characterized in that it further comprises a system for adapting voltages (11) to adapt the network voltage to the voltage of synchronous rotary electric machines, comprising two transformers, one reducer (15), connected between the network (1) and the second synchronous rotary electric machine (34), and another elevator (16), connected between the output (47) of the source switch (14) and the equipment under test ( 4). 5. Test bench according to any one of claims 1 to 3, characterized in that it also includes means for processing voltage, current and power signals for recording measurements for the tests to which it is intended. 6. Test method implemented in the bank of claims 1 to 5, characterized in that to perform the test of electrical equipment connected to electrical networks against "voltage dips" comprises the following sequence of actions: - First, with the mechanism of change of shots of the transformers, the voltage of the transformers is adapted of the ADT module (11) to the value of the mains voltages at the point of connection, subsequently, in the phase selection device (39), the type of test is programmed (single phase, two phase or three-phase) and in the control module (9) the desired profile for the temporal evolution of the "tension gap" during the test; to Then, the system is connected to the supply line (2) and the device is kept empty, disconnected from the device rehearse (4); so arranged the system, the maneuver is executed programmed to make the adjustments in empty; - Once the previous adjustments have been made and, through coordinated action on the REG control unit (8) and on the connection automation (14), the system is activated and perform the protocol of maneuvers that reproduce the desired profile for the temporal evolution of the "tension gap" in each of the phases of the network, during the test.