ES2296554B2 - GENERATOR OF PROGRAMMABLE TEMPORARY PROFILE VOLTAGE HOLES FOR TESTING ELECTRICAL EQUIPMENT AND ITS OPERATION PROCEDURE. - Google Patents

Abstract

Profile Voltage Gap Generator programmable time for testing electrical equipment and its operating procedure.

It is a power generation equipment composed, essentially, by an induction regulator, a drive to establish the position of its axis, and a connection automation

Said induction regulator is inserted in series between the network and the equipment to be tested through the automation of  connection, consisting of three multipolar contactors with limiting impedances The set is complemented by two three-phase transformers with sockets, one connected between the network and the device, and another between the device and the computer to test.

The team generates a three-phase system of tensions where the temporal evolution of its effective values responds to a previously programmed pattern. It constitutes a electrical equipment test tool, to evaluate your operation during the "voltage gap" contingency, Especially useful in wind turbines.

Description

Profile Voltage Gap Generator programmable time for testing electrical equipment and its operating procedure.

Technical sector

The invention falls within the technical sector of the quality and reliability of electrical service, more specifically in related to generator response evaluation systems electrical and large receivers in High Voltage, in front of gaps tension.

State of the art

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 1 second. Usually these gaps are caused by the impact on the point in question, of a short circuit or "fault" somewhere else in the network, more or less distant, which is correctly cleared 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.

In that order of things, the current legislation incentive through a specific supplement (5% of the rate), to wind farms that can contribute to the continuity of supply against voltage dips, and install the equipment regulation necessary for this (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 is seen 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 Electrical Service and its design is oriented to the accreditation of the behavior of receiving equipment, such as industrial drives and all type of semiconductor devices, facing 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, US Patent 6,285,169 B1 entitled "SAG GENERATOR WITH SWITCH MODE IMPEDANCE "and US 2003 Patent 0230937 A1" SAG GENERATOR WITH PLURALITY OF SWITCH TECHNOLOGIES "correspond to equipment of generation of voltage dips that use electronic equipment whose maximum achievable power is limited to a value less than 100 kW, to be able to replicate the wave correctly. This limit is clearly lower than the one required for wind turbine testing or large receivers (2-3 MW), application to which the invention is mainly intended.

The equipment referred to in both WO0060430 US 00 5,920,132-A "Non rotating portable voltage sag generator", and in the article by Collins ER, 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 . Rodríguez "Procedure for measuring the response of wind turbines to voltage gaps with the ULISES mobile unit" ( Revista Energía, No. 191. Mar / April 2006 ), does not have this power limitation because they are composed of electromagnetic devices, therefore they are closer to the object of the invention. In the first two autotransformers are used, while, in the last mentioned, a synchronous generator is used. These equipments could manipulate power values in the order of those required by wind generation systems or large receivers (2-3 MW), although they pose various problems associated with scaling. However, the temporal profile of the voltage gap that is generated with said equipment differs from that required by wind generation systems, in relation to the temporary evolution of the voltage during its recovery (PO12.3 BOE 254 of 24 October 2006). While it must present a profile with a sharp initial fall, followed by a progressive ramp-shaped recovery, the above-mentioned hollow generators are only capable of causing sudden drops and voltage recovery.

Detailed description of the invention

The present invention is about a generator Tension gaps with programmable temporal profile which, composed by electromagnetic devices, it is able to 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 adaptive time evolution profiles to the "employer" established by the applicable regulations in each case and without the need to cause "real" network failures.

The generator is mainly composed of two systems:

- A power system whose basic element is an induction regulator (6) that has a control system of the position of its axis (7, 8, 9, 10). Said induction regulator it is inserted in series between the network and the equipment to be tested through of a connection automation (14), consisting of three contactors multipolar (15, 16 and 17) medium voltage and an integrated system limiting current connection, consisting of three impedances (40). The previous set (5, 14), has a system for voltage adaptation (11) composed of two equal three-phase transformers (12, 13), one connected to the input, between the network (2) and the device, and another, at the output (3) between the device and the equipment to be tested. Both transformers they have mechanisms of change of shots with capacity to regulate Your assigned voltage level.

- A control system over the system previous power consisting of a programmable device (10) which sends connection and disconnection orders to the automation of connection (14) and to the axis position control system of the induction regulator (7, 8), depending on the setpoint of Desired temporal evolution for tension.

At this point, it should be remembered that a induction regulator is basically an induction generator which has a mechanism that does not let the axis of the shaft turn freely rotor. In fact, this mechanism has the function of being able to modify the relative position of the rotor, relative to the stator and keep said position. Therefore there is no continuous turn as would happen in a motor or induction generator.

The main characteristics that differentiate The equipment that is intended to be patented of the existing ones, are:

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Get a profile of the evolution of amplitude of the tension of the "hollow" adjustable to the ramps of recovery of a real tension gap.

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Provides continuous regulation of the slopes of each tension ramp during the period of recovery, directly modifying the magnetic coupling of the windings of an electromagnetic machine, which provides sine waves of adjustable amplitude but of frequency invariant.

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By not use electronic converters to perform regulation Continuous voltage, does not introduce any distortion in the wave of voltage and current, during the gap.

The operation procedure of this generator It includes the following actions:

- First, the tension of the ADT module transformers (11) to the value of the voltages of network at the connection point using the tap change mechanism of the transformers,

- Second, the type of test is programmed (gap single phase, two phase or three phase) and the desired profile for the temporal evolution of the "tension gap" during the test in the programmable device (10) of the REG module (8);

- Third, the system is connected to the line of connection (2) and the device is kept empty, disconnected of the equipment to be tested (4); and the programmed maneuver is executed to Make the settings empty.

- Finally, made these adjustments and, through coordinated action on the REG control unit (8) and on the connection automation (14), the system is activated and performs the maneuver protocol that has been programmed and that reproduce the desired profile for the temporal evolution of the "hole voltage "in each phase of the network, during the test. That is, the equipment to be tested is connected (4), and the system for carrying out the programmed test.

Brief description of the drawings

Figure 1 represents a general scheme of set of the invention, where the four are distinguished fundamental components or modules that constitute your structure:

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DEC module ( Decalator ) identified as 5, which is the power equipment that generates a modifiable effective value voltage, where 6 is an asynchronous winding rotor machine and 7 is a servo motor.

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REG module ( Regulator ) identified as 8, which is the control equipment of the DEC module described above, where 9 is an electronic converter and 10 is a control system consisting of a programmable device that sends orders to the DEC module and the CNX module.

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ADT module ( Adapter ) identified as 11, is the equipment for adapting voltage levels, where 12 and 13 are 2 transformers, respectively reducer and voltage booster, with an assigned assigned voltage level by means of sockets.

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CNX module ( Connector or connection automatism ) identified as 14, which governs the execution of the device connection and disconnection maneuvers, 15 16 and 17 are 3 groups of 3 medium voltage unipolar contactors.

The device input connects to the line three-phase high voltage connection 1, through terminals 2. The device output is done by terminals 3, which connect to the input of the equipment to be tested, arranged in the terminals 4.

Figure 2 represents a detail scheme of the DEC module for the modification of the voltage by means of an induction regulator, where 18 is the three-phase winding of the rotor of the asynchronous machine 6, 19 is the three-phase winding of the stator of said machine, 20 is the neutral terminal of the rotor, 21 22 and 23 are the input terminals of the rotor phases, 24 25 and 26 are the input terminals of the stator phases, 27 28 and 29 are the output terminals of the phases of the Stator, 30 is a transformer of adaptation of stator rotor voltages, 31 32 and 33 are the output terminals of the DEC module.

Figure 3 represents a detail scheme of the REG module for dynamic regulation of the voltage profile, where 34 is the voltage setpoint signal, where 35 is the system designated as block BL1 for setting the voltage profile, where 36 is the system denominated as block BL2 that constitutes a voltage regulator circuit, where 37 is the position setpoint signal, where 38 is the system called as block BL3 which constitutes a position regulator circuit, where 39 is the command setpoint signal for the servomotor.

Figure 4 represents a detail scheme of the power circuit of the CNX connection module , where 15, 16 and 17 are three medium voltage contactors and 40 are three impedances.

Figure 5 represents a detailed scheme of the ADT module of voltage adaptation transformers.

Figure 6 shows a detailed scheme of the disconnected tap system of the transformers of the ADT module , where 41 is a tap selector, where 42 is a polarity switch.

Figure 7 shows an example profile of the Temporary evolution of tension during a gap.

Figure 8 is a general scheme of the assembly of the invention, somewhat more simplified than that of Figure 1.

Description of an embodiment of the invention

A mode of realization of the team, which can serve as an example of application, while allowing to describe what can be done with the invention It should be clarified that, at all, it is not the only one way of operating the device object of this invention.

The input terminals (2) must be connected, in direct sequence, to the three-phase rush line (1). The output terminals (3) must be connected, in direct sequence, to the terminals of the equipment under test (4). It is formed by Four subsystems or modules:

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DEC module (5): It consists of an asynchronous (MA) medium voltage winding rotor machine (6) that has an SM servomotor (7) for positioning its axis.

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REG module (8): It consists of an electronic converter (9) and a feedback control system (10) that regulates the position of the DEC module axis (5).

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ADT module (11): This module consists of 2 identical transformers with sockets (12, 13), its voltage ratio is variable 10-30 kV in primary and 6.6-3.3 kV in secondary.

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CNX module (14). This module consists of 3 groups of unipolar medium voltage contactors (15, 16 and 17), with independent control, and their control circuitry to generate unbalanced, single-phase and two-phase voltage gaps. Each of these groups has 3 contactors, one per phase.

These modules have the following mode:

The asynchronous machine (6) of the DEC module has 2 three-phase windings, one arranged in the rotor (18) and another in the stator (19). The rotor circuit is composed of three coils in star connection with the neutral one accessible by terminal (20), being (21, 22 and 23) the respective input connection terminals to each coil. The stator circuit consists of 3 coils, with their 6 terminals accessible. The input terminals are (24, 25 and 26) and the output terminals are (27, 28 and 29). The rotor shaft of the machine is coupled to a servomotor (7) with the capacity to modify, in load, the position of the rotor shaft. The position angle of its axis determines the voltage at its output terminals. The expression that establishes the relationship between the effective value of the input line voltages U e and output U S of said DEC module , through the position angle α of the rotor shaft, is as follows :

U_ {S} \ approx U_ {e} \ sqrt {2 (1 - cos \ \ alpha })

The values of the assigned stator voltage and rotor, will be chosen from the standardized values (6.6 kV; 6 kV; 4.16 kV; 3.3 kV; etc ...) depending on the power of the equipment, and they can be different for the rotor and for the stator, if so deemed convenient. The rotor and stator coils are connected each other, or directly, connection only possible in the case of that the assigned voltages of both circuits are identical, or well, as the scheme shows, in the most general case, through of a three-phase transformer (30) for adapting the levels of rotor voltage and voltage regulator stator, that is, whose transformation ratio matches the stress ratio assigned stator / rotor. Modifying the relative position of the rotor coils (18) with respect to those of the stator (19), is modified the amplitude of the resulting voltage without modifying the frequency nor the sine waveform.

The output of the REG module (8) is connected to the power supply of the servomotor (7) and, through it, regulates the position of the axis according to the voltage reference (34) established for the system at each instant of time.

In this module, the temporal evolution of the desired profile of the setpoint signal v ref (34) that must follow the effective value of the voltage applied to the equipment to be tested is programmed from a PC. This block (35) allows to program in situ the desired voltage profile for the signal. Subsequently, the voltage regulation (36) is carried out, taking into account the error on said setpoint value v ref and a reference value is established for the signal corresponding to the position angle of the rotor shaft α ref (37). ). Another regulator (38) regulates the position angle of the rotor shaft, taking into account the error on said setpoint value? Α {ref} and establishes the command signal (39) on the actuator of the SM system servomotor. The actuator is composed of an electronic power converter (9) with position control on the axis of a permanent magnet servomotor.

The sequential connection of the invention to the equipment to be tested is established through the CNX module . It is a set of 3 groups of unipolar medium voltage contactors C1 (17), C2 (16) and C3 (15) of fast action, to enable the safe maneuver of connection and disconnection of the group during the test, and its circuitry of control. Each of these groups has 3 contactors, one per phase and they are connected as follows:

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The group of contactors C3 (15) directly connects the network to the equipment to be tested.

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The group of contactors C2 (16) connects the output of the DEC module to the equipment to be tested through an impedance per phase Z2 to limit the current (40).

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The group of contactors C1 (17) directly connects the output of the DEC module to the equipment to be tested.

The logic of action of these contactors for the connection maneuver and start of the test, it is the next:

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The starting conditions are established with the group of contactors C3 (15) closed and the other two, C1 (16) and C2 (17), open. This keeps the test equipment normally connected to the network with its usual tension

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The end of the maneuver means that the group of contactors C1 (16) is closed and the other two, C2 (17) and C3 (15), open, so that the voltage of the equipment to be tested is established by the DEC module .

The temporal sequence of action of each group of contactors, is detailed in the attached Table:

one

The voltage of the connection line of the equipment that is intended to be tested with this invention is usually between 10 and 30 kV, while the assigned voltage of the asynchronous machine of the DEC module , which establishes the temporal profile of the voltage during the test is different (6.6; 3.3 kV; etc .; as appropriate). The ADT module (11) has two identical transformers, one at the input (12) and one at the output (13), to adapt these voltage levels.

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The higher voltage side of the TRAF-L input transformer (12) must be connected to the terminals of the supply line, and the lower voltage side must be connected simultaneously to the input terminals of the CNX module (14) and of the DEC module (5). The higher voltage side of the TRAF-G output transformer (13) must be connected to the output terminals towards the equipment to be tested (3), and the lower voltage side at the output terminals of the CNX module (14).

The device of selection of sockets that has the winding of greater tension (20 kV) of each one of the transformers, is composed of a selector "S" (41), of 10 sockets, arranged in said winding of high tension, with a jump of 1 kV per socket and a switching device "C" for polarity change (42). The lowest voltage winding is of the stator voltage level of the asynchronous machine of the DEC module (6.6; 3.3 kV; etc .; as the case may be). In this way, installations connected to lines between 10 kV and 30 kV can be tested.

The equipment used includes the sensors of signal, and data acquisition card for processing voltage, current and power signals, and for recording test measurements.

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 7 on the terminals of a wind turbine (equipment to be tested) connected to a 30 kV line

1. Preparation of the gap generating equipment for tension

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CNX module (Fig 4). This module is kept deactivated with all contactors (15, 16 and 17) in the rest position (open). This module will make the necessary connections to execute the maneuver.

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ADT module (Fig 5). The connection of both transformers is prepared by setting the switch (42) to (+) and connecting the 5th socket of the higher voltage side (AT).

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REG module (Fig 3). The defined temporal voltage profile is programmed (see figure 7) and implemented in block BL1 (35) of the REG module . The hollow depth adjustment is made to the desired value (0.2 pu, in this case) in a vacuum, establishing the initial position of the rotor angle α_ {ref \ _0}. Starting from this initial reference value, the control system will dynamically adjust this reference during the test. On the other hand, the correct operation in vacuum of the system is checked, comparing the voltage at the output of the DEC module , with the reference.

2. Execution of the trial

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CNX module At instant "1" (Fig. 7), the CNX module is activated to perform the maneuver protocol on the contactors described above (see data in the Table ), to make the transit from the disconnection of the generator from the network to the connection to the output of the DEC module .

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DEC module and REG module . During the period "1-2" (500 ms), the regulation device on the servo motor of the REG module (8) maintains the axis around the initial position angle, maintaining the voltage at the output of the DEC module (5) in the 20% of the assigned value of the generator voltage. During the period "2-3" (500 ms), the REG module (8) tracks the voltage recovery ramp up to 80% of the assigned value. During the period "3-4" (14 s), the REG module (8) tracks a new voltage recovery ramp, from 80% to 95% of the assigned value. At this point, the test ends following the usual wind turbine disconnection protocol.

Claims (5)

1. Profile tension gap generator programmable time for consistent electrical equipment testing in: - A power system consisting of a induction regulator placed in series between the network and the equipment to test by means of a voltage adaptation system, also in series, and a connection automatism that bridges or allows said Connection; where the induction regulator is formed by a asynchronous machine (6), which has 2 three-phase windings, one arranged in the rotor (18) and another in the stator (19), and where the rotor circuit is composed of three coils in connection star with the neutral accessible by the terminal (20), the circuit of the stator is constituted by other 3 coils, with their 6 accessible terminals, and the machine's rotor shaft is coupled to a servomotor (7) with the capacity to modify, in load, rotor shaft position, position that is regulated to through a control system (8, 9, 10); where the automatism of connection (14) consists of 3 groups of contactors unipolar medium voltage (15, 16 and 17), independent control, and its control circuitry and an integrated system for limiting connection current, consisting of three impedances (40); and where the system for voltage adaptation (11) is composed of two equal three-phase transformers (12, 13), with a voltage level  assigned adaptable by shots. - A control system over the system previous power consisting of a programmable device (10) which sends connection and disconnection orders to the automation of connection (14) and to the axis position control system of the induction regulator (7, 8), depending on the setpoint of Desired temporal evolution for tension. 2. Voltage gap generator according to claim 1, characterized in that each of the poles of the multipolar contactors (15, 16 and 17) is replaced by a unipolar contactor with independent control, which generates unbalanced voltage holes: single phase or two phase. 3. Voltage gap generator according to claims 1 or 2, characterized in that it includes a three-phase transformer (30) for adapting the rotor and stator voltage levels of the voltage regulator, which is connected to the input terminals of the rotor coils (21, 22, 23). 4. Voltage gap generator according to claims 1, 2 or 3, characterized in that it includes the signal collectors, and the data acquisition card for treatment of voltage, current and power signals, and for the recording of measurements of the essays. 5. Operating procedure of the voltage profile generator with a programmable time profile for testing electrical equipment connected to High Voltage networks characterized in that it comprises the following sequence of actions: - First, the tension of the ADT module transformers (11) to the value of the voltages of network at the connection point using the tap change mechanism of the transformers, - Second, the type of test is programmed (gap single phase, two phase or three phase) and the desired profile for the temporal evolution of the "tension gap" during the test in the programmable device (10) of the REG module (8); - Third, the system is connected to the line of connection (2) and the device is kept empty, disconnected of the equipment to be tested (4); and the programmed maneuver is executed to Make the settings empty. - Finally, the equipment to be tested is connected (4), and the system for testing is activated programmed.