Method and device for detecting of malfunction of vacuum breaker of live tap changer

FIELD: electricity.

SUBSTANCE: invention relates to the method of detecting of malfunction of the vacuum breaker in a live tap changer in which the tap changer contains a housing filled with oil, a diverter switch comprising a mobile contact (MC, RC) and, at least, one vacuum breaker (MVI, RVI) designed with a possibility of interruption of the current passing through the mobile contact of the diverter switch. The method includes the repeating stages during which the content of hydrogen in oil is determined and the existence of malfunction of the vacuum breaker (MVI, RVI) is identified on the basis of measurement of the content of hydrogen in oil.

EFFECT: decrease of risk of false identification of malfunction with an immediate emergency shutdown of the transformer.

11 cl, 9 dwg

 

Area of technology

The invention relates to a method and apparatus for detecting a malfunction of the vacuum interrupter in the tap changer under load, in which the tap changer comprises: a housing filled with oil, divertirsi switch (3), comprising a movable contact (MC, RC) and at least one vacuum interrupter (MVI, RVI), is arranged to interrupt the current passing through the movable contact diverting switch.

Prior art

The tap changer is a device that is used with transformatsii to regulate voltage levels. This is achieved by changing the tap changer number of turns in the winding of the transformer.

Switches on-load tap (device POPN) usually contain divertirsi switch and the selector branches, working as a unit to effect a transfer of current from one branch to the next.

Divertirsi switch shall have complete circuit and an open circuit with a current under load, whereas the selector branches pre-selects the branch to which divertirsi switch transfers the load current. The selector branches running without load. When you want to change the output power of the transformer � one voltage level to another, this is done first by connecting the selector to that branch of the transformer that corresponds to the new voltage level, while divertirsi switch is still powered from the existing voltage level.

The connection of the selector, thus, there is no current load. When the selector is connected with a branch to a new voltage level, the switching operation using diverting switch so that the output current comes out with a new branch point of the transformer. When the transformer has a plurality of branch points, switching is usually performed only between two branch points that are close to each other from the point of view of voltage. If you want regulation to a larger value, it is gradual. Divertirsi switch of the above type typically used to control power or distribution transformers. The device POPS may also be advantageously used to control other types of electrical devices, such as products for transmission and distribution of electricity, such as reactors, industrial transformer, the phase-shifting device, capacitors or the like.

Work diverting switch includes switching from one tzepina another with a guaranteed occurrence of electric arcs. Divertirsi switch along with all the subsystems located in the tank and immersed in oil. The tap changer under load contains a pot with butter, divertirse switches and subsystems.

The oil in the tank acts as an electrical insulator and cooler to remove heat generated in POPN. The oil will also extinguish the arc that occurs when switching. Arcing when working POPN will contaminate the insulating oil and cause erosion of the switch contacts.

It is known that in order to prevent arcing in oil, for switching operations in which an arc occurs, use a vacuum breakers or vacuum switches. The wear of the electrical contact and arcing will occur only in the vacuum switch. For the relevant procedure from the electrical point of view divertirsi switch of this type is provided with at least one main branch and one resistive branch, each with vacuum breaker.

Divertirsi switch of the above type are known, e.g. from US 5786552 (D0). Described there divertirsi switch, thus, has one main branch and one resistive branch, in the steady state are connected in parallel and connected to the output line. Each branch is equipped with a vacuum breaker � contact, connected in series with it. They work in sequence, when it switches diverting switch in which it is important to ensure the work of main branch to the resistive branch to the device POPS, but for some breakers load the main branch is not working to the resistive branch. Thus, the vacuum switch of the main branch can be designed to interrupt only the current load, and vacuum switch resistive branches to an interrupt occurring circulating current. In the case of the reverse sequence to the vacuum switch of the main branch will have to interrupt the sum of these currents, and therefore it must be estimated accordingly.

US 3206569 (D1) illustrates the tap changer (8) equipped with vacuum circuit breakers. The tap changer is connected (5) with the main transformer (1). The tap changer is separated from the transformer and is provided in the same housing and the liquid as the transformer (Fig.2), or in a separate building and separate the liquid (Fig.3). The cover (39), given for the collection of gas located above the tap changer, and the cover (39) is arranged to transfer gas to the sensor (40) of gas. The sensor (40) of the gas is of the type which senses the presence of hydrogen and a hydrocarbon gas�. If the vacuum switch is faulty (see column 5, lines 11-25), contactors (9, 10) are opened, and an arc occurs, which creates a gas bubble. The presence of gas is detected by a sensor, which generates a warning. Thus, the warning indicates that the vacuum switch is defective.

In the event of a malfunction of the vacuum breaker auxiliary contact system in the device POPN can interrupt the current limited number of times, depending on the type of device POPN and load, possibly between 10 and 500 times.

If the auxiliary contact system, i.e. the movable contact diverting switch, forced to interrupt a current of more than this limited number of times, the wear of auxiliary contacts by arcing causes the contacts to close the circuit and allow the current to flow. If the auxiliary main contacts are not able to withdraw, you can expect two things:

1. The primary circuit is open and the load is on the resistive circuit. In continuous full load current limiting resistor, the resistor will eventually melts and breaks the circuit, which will lead to arcing inside the device POPN. It is hoped that this arc is detected, and this should lead to immediate emergency shutdown system POPS-transformer. The result will be lasting repairs� or replacement diverting switch, and during repair of the transformer will be disabled.

2. Stable arc is formed between the auxiliary contacts that may lead to a short circuit between two phases that will lead to serious damage, for example, explosion or fire. If you're lucky, stable arc goes out, and then you need to go back to item 1.

Thus, it is important to monitor the operation of the vacuum breakers to prevent possible damage mentioned above. At the moment there are no simple and reliable method of detecting malfunction of the vacuum interrupter in the tap changer and the seriousness of the fault.

ABB provides a system for monitoring and processing data, called TEC (electronic control transformer), which monitors transformers and switches branches, such as the device POPN. System with TES equipped with sensors and measuring blocks and configured to measure and monitor the condition and operation of the tap changer or transformer. It also includes a computing unit for computing in the processing of measurement data. For example, the TES system measures and monitors the temperature of the oil in the bottom and the top of the transformer tank and calculates the points of the maximum temperature of heating coils of the transformer. Each�mi data are monitored, are the voltages and currents at the input high and low voltage, ambient temperature, aging, thermal aging, aging relative, depending on temperature, maximum load, load factor, overload capacity, the moisture content in the oil, the hydrogen content in the oil, expressed in millionth, the state of the cooling equipment, the position of the tap changer, the status of sensors, for example, malfunction, etc TES also configured to display the reference values such as the reference value of the upper and lower temperature.

The hydrogen sensor is located in transformer oil, and connected to the TES, it provides a measurement of the hydrogen content in the transformer, which indicates the burning of an electric arc or spark discharges in the transformer of the device POPN.

TES are described in more detail in the manual “Intelligent Monitoring System, Type TEC. User's manual”, which is published on the websitehttp://www.abb.com/electricalcomponents.

Moreover, when the automatic control unit tap-changer gives the command for switching the electric drive mechanism of the tap changer, which subsequently leads to a change in the branch in the tap changer, this event is recorded in�numeral system TES.

Summary the essence of the invention

The object of this invention is the provision of a method of detecting a malfunction of the vacuum interrupters of the tap changer under load (device POPN).

This problem is solved by using the method described in paragraph 1 of the claims.

The invention can be used to improve the performance of the TES system from ABB and also similar systems monitoring and management for switches branches from other suppliers.

The method includes repeating the measurement of hydrogen content in the oil of the switch housing branches, and determining whether there is a malfunction of the vacuum interrupter according to the measurement of hydrogen content in the oil. Provides a method of monitoring the hydrogen content, and this makes it possible to monitor its changes.

In addition, the step of determining may include mobile switching of the tap changer, for example, the number of times the tap changer switch, or how often he switches to determine the fault. The result of the measurement of hydrogen content compared to the estimated content that is based on the history of the switches, and the method indicates a fault only in the case when the measured content differs from RAS�ethno content by a certain value, i.e. when the difference is greater than the threshold value.

May be combined hydrogen sensor described above and TES system, but the sensor should be located in the oil tap changer instead of transformer oil (or as an addition to the sensor in transformer oil), and must be implemented other analysis, as measured is no longer a characteristic of the transformer. Furthermore, the use of tap-changer is tracked by monitoring the number of operations that is used for analysis of hydrogen content and change of hydrogen content in the oil.

Another object of this invention is the provision of a device for detecting malfunction of the vacuum interrupters switch branches.

This object is achieved by a device under item 10 of the claims.

The device includes a housing of the tap changer, oil filled, is provided with a sensor (10) for repeated measurements of hydrogen content in the oil, and a computing unit configured with an analysis of measurements of hydrogen content in the oil and determining the presence of a fault in the vacuum interrupters (MVI, RVI).

The object of the invention is solved by understanding that in the event of failure of the vacuum interrupter, the current is interrupted not vacuum �derivately, and auxiliary contact system. Auxiliary contact system is forced to interrupt the current, thereby creating an arc in the oil. These arcs are combined with the known fact that the arc in insulating oil increase the content of hydrogen in the insulating oil. The hydrogen sensor, detecting the absolute value of the hydrogen in the oil or the rate of change of hydrogen in oil, can be used to detect that the vacuum breaker can interrupt the current, and, therefore, it is possible to detect a malfunction of the vacuum interrupter.

In another embodiment of the present invention the method further comprises the steps in which:

- save the measurement of hydrogen content in the oil, and

- determine a malfunction in the vacuum switch (MVI, RVI) based on the measurement of hydrogen content in the oil and at least one stored measurement of hydrogen content in the oil.

The detection of a fault in the vacuum switch may be implemented by comparing the measured level of hydrogen content in oil with a fixed maximum level of hydrogen content and/or comparison of the increase in the hydrogen content in the oil for a period of time saved by using previous measurements of hydrogen content in the oil.

In another implementation of this embodiment of�of Britania method further comprises the step, on which:

- perform the action in case of failure detection in the vacuum switch.

The action may include sending a warning to the management system of the tap changer of the transformer. The alert may also be sent to the overall control system of the station. The action may also consist in the assumption of only a limited number of critical alarms without overloading diverting switch. The action can also be to stop moving diverting switch. The selected action may depend on the level of hydrogen content in the oil or on the degree of increase in the level of hydrogen content in the oil.

When a serious fault is detected vacuum breaker device POPN should be immediately stopped or limited to a certain number of critical alarms without overload, if it is considered critical for the operation of the system in which it operates. A limited number of positives diverting switch may be less than 200 or less 20 to check the device POPN service personnel.

When the device POPN stopped, the transformer can still be used, but the voltage level of the already unmanageable, however, this is the preferred condition as compared to the case when �not a helluva lot detected, and the device POPN subjected to severe damage.

In another embodiment of the present invention the step of determining the presence of a fault in the vacuum switch contains repeating stages, in which:

- receive data operation of the tap changer;

- calculate the expected change of hydrogen content on the basis of a mathematical model of the tap-changer data and the operation of the tap changer, and

- determine a malfunction of the vacuum interrupter based on the calculated expected changes in the content of hydrogen and at least two measurements of hydrogen content.

Re-implementation of phases means that they are almost continuously, or at intervals of time with seconds between them, or with large time intervals of several minutes between them. The operation of the tap changer is to determine the switching time diverting switch and the load current during switching. The model should be a natural model to predict the release of hydrogen based on the number of switches and the load current, or the model may be an analytical model based on measurements and/or previously collected data where the average release of hydrogen Vice�is based on the number of switches and the load current.

The level of hydrogen content in the oil tap changer is usually highly depends on how the switch branches, i.e. how often are switching branches, and the load currents need to interrupt.

This model is based on the detection of a malfunction of the vacuum breaker has a much lower probability of errors in comparison with a system that only compares the measured level of hydrogen content in the oil with the absolute value of the level of hydrogen content. False detection of a failure of the vacuum interrupter can lead to optional shutdown transformer switch branches. This is an optional shutdown will lead to a potential loss of power of all the connected systems, for example, industrial facilities or residential buildings that will be very expensive.

In another embodiment of the present invention detect a malfunction of the vacuum interrupter based on the condition

[H2mes(new) - H2mes(old)] - ∆H2est> eps

H2mes(new) is a parameter describing the current measurement of the hydrogen content in the oil, and it can be a single measurement or an average value or the average value of a certain number of results�of ATA measurement;

H2mes(old) is a parameter describing a previous measurement of hydrogen content in the oil, and it can be the result of one measurement or the average value or the average value of a certain number of the previous measuring results;

∆H2estis the expected change in the hydrogen content in the oil on the basis of operation of the tap changer. The operation of the tap changer is to determine the time of switching diverting switch and the load current during switching;

eps is a security setting that ensures that the vacuum fault interrupter is not defined until such time as the measured increase in the hydrogen content is not more eps. eps may be equal to the order of several ppm to several hundred ppm of hydrogen content in the oil, depending on the type of tap changer, load the freshness of the oil and the risk of false alarms.

Detection of hydrogen content and tracking in the switch branch have additional advantages are that they can be used also for detecting the presence of:

switching spark discharges that will create much less of hydrogen in the oil compared to the full arc;/p>

- partial discharges, which will create a continuous slow increase of the hydrogen content in the oil, and lead to signal the presence of hydrogen than the signal of the presence of hydrogen in the event of arcing;

serious overheating related arcs that will signal the presence of hydrogen than the signal of the presence of hydrogen in the case of arcing in the switch branches.

In another embodiment of the present invention, the computing unit is configured with the ability to send an alert to the control system in the event of detection of a failure of the vacuum interrupters (MVI, RVI).

In another embodiment of the computing facilities are an integrated part of the control system, which can be achieved with the help of a computer software product that improves the existing management program.

In another embodiment of the present invention, the computing unit is configured with the ability to send a signal to the control system to stop or restrict movement diverting switch in case of detection of a failure of the vacuum interrupters (MVI, RVI).

In another embodiment of the present invention, the computing unit configured to receive information op�the radio switch branches, and a computing unit configured to compute the expected change in the hydrogen content and to compare the expected change of hydrogen content with the parsed results of measuring the hydrogen content in the oil to determine a malfunction of the vacuum interrupters (MVI, RVI).

Brief description of the drawings

The invention is further illustrated by a description of preferred embodiments with reference to the accompanying drawings, in which:

Fig.1 schematically depicts the tap changer under load in the transformer in the embodiment of the implement according to the invention;

Fig.2A to 2E schematically depict the switching of the tap changer under load without vacuum interrupters;

Fig.3A-3h schematically depict the switching of the tap changer under load with vacuum circuit breakers;

Fig.4 depicts a situation in which the arc will burn in the auxiliary switches in the tap changer under load with vacuum interrupters;

Fig.5 is a schematic view of the tap changer under load;

Fig.6-8 are schematic views of modifications of the hydrogen content in the oil according to the time switch branches, as well as different levels of warning and alarm;

<> Fig.9 depicts a variant embodiment of the invention provides an alternative arrangement of the tap changer under load Fig.1.

Description of preferred embodiments of the invention

Detailed description of preferred embodiments of the invention provided below. It should, however, be understood that the present invention can be implemented in various ways. Thus, individual features disclosed here should not be interpreted as limiting, but rather as a basis for the claims and as characteristic as the basis for training of a specialist in the art to apply the present invention in virtually any appropriate scheme, arrangement, or method.

Fig.1 schematically depicts switch 2 on-load tap in the transformer 8 in the embodiment of the invention according to the present invention. The selector 1 branches established after diverting switch 3. Moving the device POPN carried out using the energy obtained from the electric drive mechanism 9 mounted on the wall 8 of the transformer. The movement from the motor 9 is transmitted through the shafts 6' and 6” and a conical gear 7. Expansion tank 5 provides sufficient amount of oil in the device POPS at all temperatures.

Remove�10 PTS hydrogen sensor is immersed in the oil tap changer, a situation that the drawing is only approximate, it can be located anywhere in the body.

The device 10 of the hydrogen sensor sends a signal to the control unit 11 of the actuator, which controls the movement of the motor 9 to actuate divertirsi switch 3.

Alternatively, the device 10 of the hydrogen sensor sends a signal to the computing unit, computing unit also receives signals indicating the movement diverting switch, such as a strong team work for the engine 9, and the signal team work is accepted, for example, from the engine 9. And the transformer 8, and the device POPN 2 filled with oil, but have different housings, and the oil in the device POPS and the oil in the transformer never come in contact. You can also place the device POPS outside of the transformer tank.

Fig.1 depicts a first variant of implementation, in which the sensor 10 is connected to the block 11 for controlling the drive, which includes a means for determining the presence of a fault on the basis of measurements of hydrogen content. The management block 11 may be included in the control system of substation, transmission of electricity.

Fig.9 depicts an alternative implementation, in which the sensor 10 is connected with the computing unit 12 that includes a means of determining the presence of nei�pevnosti based on the content of hydrogen. Computing unit 12 in Fig.9 is also connected to the electric drive mechanism and receives signals from the electric drive mechanism, when the tap changer moves. These signals may be the signals of the team, which mechanism 9 of the drive receives from the unit 11 for controlling the drive via the control connection of the actuator, which connects the unit 11 for controlling the drive motor 9. Implementation options with Fig.1 and 9 include the location of the sensor 10 in the oil tap changer, wherein the sensor transmits the measurement results to the computing unit 11, 12. The connection may be achieved by transmitting analog signals from the sensor, and these analog signals are converted into digital data, for example, using the module input/output (I/O), which selects analog data processing and incorporating Converter AC to DC current and a means for digital communications, such as the possibility Ethernet connection, and this unit adopts analog electrical measurement signals from the sensor, converts the signals into digital data, which it then transmits via Ethernet to the computer control system, for example, a substation. Alternatively, the sensor 10 includes a digital processing means and communication, and selects the measurement results in data that is transmitted on the Vacha�slitely the control unit substation with, for example, digital data bus. Thus, the device 10 of the hydrogen sensor sends a signal to the computing means 11, 12 which are arranged to determine the presence of a malfunction of the vacuum interrupter based on the content of hydrogen, preferably, the history of this content, or changes in the content of hydrogen. Computing means suitable manner is also made use of data on the operation of the tap changer, and use these data to improve analysis to best determine the presence of a malfunction of the vacuum interrupter. Thus, by switching the tap-changer can be evaluated by evaluating the content of hydrogen, so that the expected level of hydrogen content on the basis of normal change of hydrogen content and also increase the amount of hydrogen that occurs when switching, can be used instead of only fixed dangerous levels of hydrogen content. The computing means may be achieved by a computer program which, when installed on the host PC substations for power transmission, improves the performance of the control system by adding the function of determining the presence of a malfunction of the vacuum interrupter in accordance with the Fig�the group. Thus, the computer program will make it possible to use signals from the sensor of hydrogen, suitably mounted inside an oil-filled device POPN, to determine whether failure of the vacuum interrupter. The computer program also provides a means of using signals indicating the movement of the device POPS to further Refine the definition. Signals that indicate movement, can be a strong mechanism of the actuator 9, already present in the control system, or can be taken action to ensure proper signals in systems that previously have not used them. The signals are appropriately taken from the mechanism 9 of the drive when it is running, or from the unit 11 to the drive control, which feeds these command signals to the motor 9.

Fig.2A to 2E schematically depict the sequence of switching of the tap changer under load from position 6 to position 5 on the winding of the transformer.

The main flow of electric currents are indicated by grey arrows.

The sequence displays a symmetrical lever loop. This means that the main switch contact diverting switch opens before the current limiting resistor is included on etapirovaniya. This ensures maximum reliability when the switch is in overload condition.

At full load the interrupt occurs at the first zero value of the current after the separation of the contacts, which means the average time of arcing 4-6 MS. The total time of a complete sequence is in the order of 50 milliseconds. The tap changer mechanism of the actuator is approximately equal to 5 s/step.

Fig.2A: the selector contact V is connected to the branch 6, and the selector contact with an offshoot of 5. Primary contact x skips the load current.

Fig 2b: Primary contact x parted. The load current passes through the resistor Ry and the resistor contact y.

Fig.2C: Resistor contact u is closed. The load current is distributed between Ry and Ru. The circulating current is limited by the resistance is equal to Ry plus EN.

Fig.2d: Resistor contact y parted. The load current passes through EN and contact u.

Fig.2E: Primary contact v is closed, resistor Ru shunted, and the load current passes through the primary contact v. The tap changer under load now in position 5.

Arc occur at any switch, when the switch opens the contact.

Fig.3A-3g schematically depict the switching of the tap changer under load with vacuum breakers. By the use of auxiliary contacts�Noah system (MC, RC) in combination with vacuum interrupters (MVI, RVI), requires only two vacuum interrupter per phase.

Fig.3A depicts the flow of current in normal operation, from x to the neutral point of the star (may also be up to the next phase). The main path of current flow is indicated by grey arrows.

When transferring the load from x to v, the sequence of operation as follows:

Fig.3b - opening of the main vacuum interrupter (MVI) and, therefore, the provision of current opportunities to flow through current limiting resistor (TR).

Fig.3C, 3d primary contact (MC) then turns to connect with v.

Fig.3E - the main vacuum breaker is then closed, which means the connection of a new branch that leads to the associated circulating current resulting from the potential difference.

Fig.3f - current limiting resistor is disconnected by opening the resistor vacuum interrupters (RVI). The load current now passes through a normal path from v to a neutral point of the star.

Fig.3g - resistor contact (RC) then turns and locks into place.

Fig.3h - finally, the sequence is completed and the following operating position is reached, when the resistor vacuum breaker is closed.

Fig.4 is an image of the same phase as that of Fig.3, with the difference that based�Noah vacuum interrupter (MVI) as a result of not killed the circuit or not interrupting the current in the core auxiliary contact (MC). When the primary contact (MS) rotates to connect with v, the current is interrupted by displacement of the main auxiliary contact (MS). Emerging arc is extinguished in the oil, but since the auxiliary contacts are not designed for repeated exposure of the arc may be damaged. If this happens more 10-500 times, depending on the current load, there is a danger of failure of the auxiliary contacts and the device POPS will be disabled. If the current is interrupted auxiliary contacts and extinguished in the oil, the concentration of hydrogen in the oil will rise quickly, and detection of this increase will be a reliable way of indicating this failure.

Fig.5 is a schematic view of the tap changer under load, which is used with embodiments of the present invention. 12 shows a switch branches formed from two main parts, diverting switch 24 and the selector 26 branches connected to each other by connections 30. Divertirsi switch 24 may include a conventional cover 28 of the housing.

Fig.6 depicts a schematic view of the possible dependence of the substance/concentration 46 of hydrogen in oil from time to time in the tap changer. The sensor measures the hydrogen content/concentration 46 of hydrogen in oil, and in the process of analysis and�measurements compare measured data with different levels of warning or alarm, for example, 40 warnings, with the first level 41 alarm and the second alarm level 42.

Each level can be associated with different actions. For example, when the hydrogen concentration exceeds a level 40 43 warnings, the control system alerts the operators of the monitoring system of the transformer or the public address system common system management station that something may be wrong with the tap changer. When the hydrogen concentration exceeds 44, the first alarm level 41, the control system alerts the operators of the monitoring system of the transformer or the public address system total system control station, and will implement only the necessary switching branches. When the hydrogen concentration exceeds 45 second alarm level 42, the control system alerts the operators of the monitoring system of the transformer or the public address system total system control station, and stops all switching branches.

Fig.7 depicts a schematic view of the possible dependence of the substance/concentration 46 of hydrogen in oil from time to time in the tap changer. The sensor measures the hydrogen content/concentration 46 of hydrogen in oil, and in the analysis of measurements made using data processing means, compares the measured consistently�ti data with different levels of alerts or alarms of increasing the hydrogen concentration.

In the area 52, the degree of increase in the measured concentration of hydrogen is greater than possible increase requiring warning, 50. In the field 53 the degree of increase in the measured concentration of hydrogen is greater than possible increase, requiring alarm, 51. Sequence analysis of 46 data may include smoothing or filtering of the measured values.

Fig.8 depicts a schematic view of a possible change of the hydrogen concentration 46 in the butter to the time switch branches, in which each switch is associated with a stepwise increase in the concentration of hydrogen. This is shown to illustrate that the analysis system must also include the switching frequency of branches or the time between the switching branches. A large number of switches 51 branches may cause a greater increase in hydrogen compared to the more rare the switches 50 branches. But the growth curve 50 with multiple switching branches may indicate a problem. The system should be capable of, and properly implemented to distinguish the cases 50, 51, and must issue a warning/alarm for the case of 50, but not for the case 51. The relative size of curves and levels of anxiety in Fig.6-8 are shown only for illustration purposes.

It is known that arcing in insulating oil bring� to the formation of hydrogen in the oil. This effect is sometimes used to monitor the transformer. He was not used to monitor the device POPN without vacuum breakers, as arcing in oil occurs in normal operation.

With the introduction of devices POPN with vacuum breaker arcing in oil in normal mode was excluded, all arcs occur in vacuum interrupters. If the arc in the oil occurs in the device POPN with vacuum circuit breakers, this indicates that there is serious damage.

For conventional devices POPN with arc quenching in oil, working in accordance with the principle of a lever of the cycle, as shown in Fig.2, are two interrupts with the occurrence of arcs at each operation of the switch. One arc is created by opening the main contact (i.e. between Fig.2A and Fig.2b), and a single arc occurs when the intermediate opening of the contacts (i.e. between Fig.2C and Fig.2d).

The arc in the main contacts has a current equal to the load current, while the current in the intermediate contacts equal to the sum of half of the load current and the circulating current. Circulating current depends on voltage and resistance of the current-limiting resistor, and thus, does not depend on the load.

Each of these arcs usually lasts for a maximum period of half of the period, and the average percent�abolitionist will be half the period, what is 5 MS for 50 Hz. The energy in these arcs determines the number of generated gas. You can accept that the formation of gas depends linearly on the energy dissipation during combustion arcs.

The main task of the device POPN with the extinguishing of the arc in the vacuum breakers is to prevent arcing in the oil. Arcing in oil leads to several drawbacks, such as increased erosion of the contact material in the NC contacts and deterioration of the oil due to high temperatures during combustion of the arc. Deterioration of oil leads to the formation of substances that reduce the dielectric strength of the oil, especially in the presence of moisture, and also increase wear on the mechanism.

Divertirsi switch interrupts the current from one branch before he connected with each other. In order to create an open circuit, the load current passes through the intermediate contacts during the time that you want the main contacts for safe termination of the current on branch 1, until then, until they connect with the fork 2.

If the interrupt load on the device POPN will not work, for example, by a failure of the vacuum interrupter, there is the danger of a connection with a branch 2 to detach the branch 1. In connection with the electrical properties of the transformer, short-circuit�mikania the same degree of regulation will lead to large currents, which will destroy not only the device POPN, but also the winding/winding of the transformer. Also there is a serious risk further injury in connection with the occurrence of fires, explosions, etc.

As a result of the fact that the switching currents is carried out by vacuum breakers, they become the main components. If they fail to interrupt the current can cause serious damage described above.

By designing the auxiliary contacts so that they can interrupt the load current or circulating current in case of malfunction of the vacuum interrupter, to achieve a higher safety margin to avoid such serious damage.

Since the auxiliary contacts are made, primarily, to conduct the current, selected materials with low resistance, but not with good resistance to arcing. It is possible to carry out the half cycle of operation, thus interrupting the maximum rated current of the load, carrying out the function as a conductor and terminating contact.

Thus, detektirovanie the unit of observation must declare the alarm before the contacts will be destroyed by burning arcs to the point where they will not be able to fully perform their functions. The goal is raising an alert to prevent�of a transformer failure. As there may be certain operations, there is no need to disconnect the transformer. Perhaps a certain number of methods of detection, such as detection using pressure detection using oil consumption (in the pipe Malorossiya), detection by fluorescence, detection by radiation, etc.

This invention implements the use of changes in the concentration of hydrogen in the insulating oil as a parameter for detecting the presence of burning arcs in oil.

This is based on the fact that burning arcs in vacuum breaker does not generate gas in the oil. However, the device POPS with vacuum interrupters for high currents typically have a shunt contacts shunt circuit of the vacuum interrupter when the device POPN is in place to avoid long transmission currents vacuum circuit breakers, as well as to protect them against short-circuit currents.

Shunt contact will generate a switching spark discharges when the current will be switched from the branch circuit for a vacuum circuit breaker due to the low inductance in the circuit. These spark discharges will generate a small amount of hydrogen. The unleashed energy, however, is only a few percent of the energy present�th arc in oil, and generation of gas matches the ratio.

Those devices POPN that do not have a shunt contacts, still have auxiliary contacts. They don't commute any current, but in the process of switching potentially they quickly opened, with the result that they have a high voltage, which causes spark discharges of small capacity. The energy in these arcing even less compared to switching spark discharges across the shunt contacts, but still, they will lead to the formation of a small amount of hydrogen in the oil after a lot of positives under stress.

Thus, the invention can be applied to various types of devices POPN, for example, in devices POPN having shunt contacts, and devices POPN without shunt contacts. The analysis, carried out with the aid of computational tools that need to be made accordingly, but its main features will remain the same.

The compositions of these gases correspond to about 75% hydrogen (H2and about 20% of acetylene (C2N2). For spark discharges small capacity would be closer to 100% hydrogen. Acetylene is readily soluble in oil with regard to its similarity with the hydrocarbons in the oil, while the hydrogen dissolves poorly.

Thanks to the analysis of the content Ogorodov oil, available cheaper and reliable measuring device in comparison with a situation where the necessary analysis of hydrocarbons. Continuous measurement of hydrogen content in transformer oil are also well-established method that has been practiced for quite a long time.

Thus, the measurement of hydrogen in transformer oil does not represent anything new. Results must be interpreted in such a way as to obtain a reliable method of observation. Interpretation should work, at least for most different applications, at low current, low operating frequency, when using another system gas release, etc.

There are two possible ways of interpreting the results of measurement of hydrogen content:

1. Alert when a certain concentration of hydrogen in oil;

2. To determine the degree of increase of hydrogen content with respect to the number of operations per unit time and the load current during switching.

Interpretation 1. With a certain amount of hydrogen will be lost to the environment, small-scale power generation will soon lead to the equality formation and removal, leading to a low and constant concentration. The alarm level can be set Nast�only high, the work was carried out throughout the range of load current, since the formation of hydrogen during combustion of arcs in oil is much stronger. Burning arcs in oil will lead to a rapid increase in the concentration that will lead to excess levels of anxiety even at low load currents. This device does not require complex logic, and is therefore simple and cheap method.

Interpretation 2. This method requires some logic and access to information about when the transaction occurs, and the load of the transformer. But it has the advantage of which is that it is more sensitive and reacts faster, especially in applications with low currents and/or low operating frequency. This method is preferably used in conjunction with the control system and protection of the transformer, such as ABB TES or something similar that already has access to the necessary data. Of course, it can be implemented by using a separate block.

Interpretation is realized in the form of a special program in the control system. Interpretation is implemented so that the change in the concentration of hydrogen is connected with the energy spark discharges released per unit time. The load current is available, as well as the number of operations per unit time. The energy of the arc, thus, can be easily Vici�Lena, and the concentration of hydrogen associated with her.

If the load is changed and/or the operating frequency is changed, the method should be performed with automatic calculation of expected values within a certain interval. This interval may be quite large, since the difference between the generation of hydrogen in normal operation and when arcing in oil is very high. Thus, the calculation need not be very accurate.

1. Method of detection of a failure of the vacuum interrupter in the tap changer under load, in which the tap changer contains:
the housing is filled with oil,
the hydrogen sensor disposed within the housing,
divertirsi switch (3), which includes the movable contact (MC, RC), and
at least one vacuum interrupter (MVI, RVI), is arranged to interrupt the current passing through the movable contact diverting switch (3),
characterized in that it comprises repeating the steps in which:
measure the hydrogen content in the oil,
transmit the measured data on the content of hydrogen in the computing unit and
determine a malfunction of the vacuum interrupter (MVI, RVI) based on the measurement of hydrogen content in the oil,
wherein the step of determining the presence of a malfunction of the vacuum�about breaker contains repeating the steps in which:
get the data of the operation of the tap changer,
calculate the expected change of hydrogen content on the basis of a mathematical model of the tap-changer data and the operation of the tap changer and
determine a malfunction of the vacuum interrupter based on the calculated expected changes in the content of hydrogen and at least two measurements of hydrogen content.

2. A method according to claim 1, further comprising the steps, in which:
save the measurement of hydrogen content in the oil and
determine a malfunction of the vacuum interrupter (MVI, RVI) based on the measurement of hydrogen content in the oil and at least one stored measurement of hydrogen content in the oil.

3. A method according to claim 1 or 2, further comprising a stage on which to perform the action, if it is determined that the malfunction of the vacuum interrupter.

4. A method according to claim 3, wherein the action includes the creation of a warning.

5. A method according to claim 3, wherein the action includes approval of only a limited number of critical operations without overloading diverting switch.

6. A method according to claim 3, in which the action contains the cessation of movement diverting switch.

7. A method according to claim 1, wherein the operations include moving contacts and the load current.

8. STRs�according to claim about 1 or 2, wherein the detection of a malfunction of the vacuum interrupter based on the condition

whereis the parameter describing the current measured hydrogen content;
- the parameter describing the previously measured hydrogen content;
- the expected change of hydrogen content on the basis of the operating data and
eps is a security setting that ensures that the vacuum fault interrupter is not defined until such time as the measured increase in the hydrogen content is not more eps.

9. The tap changer under load with a means of detecting failure of the vacuum interrupter in the tap changer under load, and the switch branches contains:
the housing is filled with oil, with diverters switch (3) containing movable contacts (MC, RC), with vacuum interrupters (MVI, RVI) connected in series with the possibility of breaking the power supply before disconnecting contacts (MC, RC), characterized in that
the housing is filled with oil, is provided with a sensor (10) for repeated measurements of hydrogen content in the oil, connected to the computing means of the configuration and is arranged to transmit signals content measurement in�Dorada computing facilities,
the interrupter of the branches contains a computing unit configured with an analysis of measurements of hydrogen content in the oil and determining the presence of a vacuum fault interrupters (MVI, RVI),
moreover, the specified computing unit configured to receive a data operation of the tap changer and computing unit configured to compute the expected change in the hydrogen content and to compare the expected change in the content of hydrogen was analyzed by measurement of the hydrogen content in the oil to determine whether the malfunction of the vacuum interrupters (MVI, RVI).

10. The tap changer under load according to claim 9, containing the system (11) control, which controls the movement diverting switch, and the computing unit is configured with the ability to send a warning to the management system when detecting the malfunction of the vacuum interrupters (MVI, RVI).

11. The tap changer under load according to claim 9, in which the computing unit is configured with the ability to send a signal to the control system to stop or restrict movement diverting switch in case of detection of a malfunction of the vacuum interrupters (MVI, RVI).



 

Same patents:

FIELD: machine building.

SUBSTANCE: invention refers to a drive mechanism. A drive mechanism for a medium voltage fuse switch comprises a base plate (10) and a front plate (11) which form an inner space enveloping a working shaft and a driving shaft set coaxially along the first longitudinal axis, the driving shaft is functionally coupled with a kinematic circuit of the medium voltage fuse switch, the working shaft (20) is fitted by a head connected to an operating handle for manual actuation of the working shaft, a spring unit consisting of two spiral springs having the first end functionally coupled with the working shaft, a clamping unit consisting of two clamping tabs set on the driving shaft, the first (61) and the second (62) unclamping units to unclamp the driving shaft and provide for its rotation. The first unclamping unit (61) provides for the rotation of the driving shaft in the direction opposite to the second unclamping unit (62).

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FIELD: electricity.

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FIELD: electricity.

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14 cl, 8 dwg

FIELD: electricity.

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FIELD: electricity.

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FIELD: electricity.

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5 cl, 1 dwg

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15 cl, 6 dwg

FIELD: electricity.

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FIELD: electricity.

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1 dwg

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FIELD: electricity.

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FIELD: electrical engineering.

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23 cl, 9 dwg

FIELD: electrical engineering.

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17 cl, 6 dwg

The invention relates to power distribution equipment, and more particularly to a power distribution device with a distribution transformer and switches

The invention relates to electrical engineering, in particular to the transformer industry, and for designs of high-voltage voltage transformers with cast insulation

FIELD: electrical engineering.

SUBSTANCE: proposed device designed to prevent explosion in transformer cooled down by large volume of combustible liquid has tank filled with combustible cooling liquid and transformer tank decompression facility. The latter has burst member with built-in explosion detector equipped with inhibitor. Inhibitor has first zones of smaller thickness compared with that of its remaining part designed for bursting without formation of fragments. Second zones of smaller thickness compared with remaining part of inhibitor are designed for burst-free bending during bursting of mentioned member. Burst member is made for bursting when pressure within tank exceeds desired threshold value. Signal of burst detector built in bursting disk actuates cooling system and prevents oxygen contact with explosive gases generated by electric arc when it comes in contact with oil.

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17 cl, 6 dwg

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FIELD: electrical engineering.

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23 cl, 9 dwg

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FIELD: electricity.

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EFFECT: simplified process of current transformer check and reduced check cost.

2 cl, 2 dwg

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