Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
  • H01H11/0062—Testing or measuring non-electrical properties of switches, e.g. contact velocity
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H3/00—Mechanisms for operating contacts
  • H01H3/22—Power arrangements internal to the switch for operating the driving mechanism
  • H01H3/26—Power arrangements internal to the switch for operating the driving mechanism using dynamo-electric motor
  • H01H3/264—Power arrangements internal to the switch for operating the driving mechanism using dynamo-electric motor using a travelling nut mechanism
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/28—Power arrangements internal to the switch for operating the driving mechanism
  • H01H33/36—Power arrangements internal to the switch for operating the driving mechanism using dynamo-electric motor
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle
  • H01H33/593—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle for ensuring operation of the switch at a predetermined point of the ac cycle

Definitions

• the present invention relates to a method for testing, controlling and re- gulating a switching device with contact parts, to a switching device and to a computer program therefore.
• the switching device comprises an electric motor and a mechanical coupling device for transforming motion from the electric motor to at least one of the contact parts.
• the switching device may comprise one or more electric motors and one or more mechanical coupling devices for transforming motion from each electric motor to at least one of the contact parts. Position, speed and/or acceleration of the at least one contact part are obtained, and position, speed and/or acceleration of the at least one contact part during operation are controlled during operation.
• the method and the switching device are particularly intended for application in medium and high voltage networks.
• the spring In a switching device using a spring mechanism, the spring will apply the same force on the contact part at every operation, so it has to be designed to operate as if a worse case current were to be interrupted at every operation. In a spring mechanism, the time delay is not constant. Spring mechanisms provide only position information with a very limited resolution. In a spring mechanism system external measurement equipment must be connected to collect information regarding the operation of spring mechanism, and must remain connected during all switching device operation s from which one wants to obtain information. In practice this means that to test a switching device, it must be taken out of service, measuring equipment must be connected and some operations must be performed.
• a control unit receives input information, which information includes information about the network condition, the movement of the mobile contact part, the movement of the rotor of the electric motor and/or instructions for an operator. Based on this information the control unit controls the motor movement by controlling the current supplied thereto.
• the movement follows a motion profile stored in the control unit and the movement is adapted to the feedback information from the input.
• This known device represents an important improvement in relation to a spring operated switching device since it offers a much higher degree of control of the motion. However, the known device is not flexible enough to obtain an optimal operation of the mobile contact part.
• the object of the present invention therefore in a first aspect is to improve the method of controlling and regulating a switching device so as to achieve a motion of the mobile contact part that is optimised with respect to timing and motion profile of the mobile contact part.
• a method of the kind specified in the preamble of claim 1 includes the specific steps specified in the characterising portion of the claim.
• the obtained information about the motion of the mobile contact part thus is used not only for the control of the contact part but is also logged and stored. Comparison of actual log entries with factory log entries gives a direct indication on whether the switching device still performs as when it was commissioned.
• the stored information may also allow observing trends and possibly predicting failures. By storing this information, each operation delivers information that is useable for every subsequent operation of the switching device. The information is processed in order to adjust for any deviation from the optimal behaviour in the previous operation so that an updated control is achieved. This allows control to be more accurate.
• the control of a switching device operation becomes more intelligent since information about a present operation as well as a previous operation contributes to the control.
• speed and/or acceleration of the at least one contact part are controlled adaptively in real-time.
• position, speed and/or acceleration of contact parts are obtained from rotor position and/or speed. Since the rotor is mechanically coupled to the mobile contact part data relating to the rotor motions are directly indicative of the corresponding motions of the mobile contact part. To obtain these data from the rotor is a very convenient and simple way of determining the motions of the mobile contact part. Detection of whether or not a switching device has started its motion will be obtained already after about 5 ms after reception of opening/closing order. This is used to send an order to another switching device in case the first switching device is not responding to an order.
• control of position, speed and/or acceleration of the mobile contact part is performed by controlling the position, speed and/or acceleration of the rotor.
• this takes advantage of the direct relationship between the rotor motion and the mobile contact part motion that is established by the mechanical coupling.
• control and regulation of position, speed and/or acceleration of the at least one contact part during operation are controlled during operation in accordance with the specific current to be interrupted.
• the required energy for operation of the switching device and the position, speed and/or acceleration of the contact parts are adapted to the present current, e.g. a short circuit current, a capacitive or inductive current or a normal load current.
• position, speed and/or acceleration of the at least one contact part is controlled during operation to obtain contact parts position, speed and/or acceleration synchronised with zero crossing of current through the switching device. It is important that a breaking operation and in particular the separation of contact parts occur at a predetermined time relation to zero crossing of the current to be interrupted.
• position, speed and/or acceleration of the at least one contact part is controlled during operation to obtain contact parts position, speed and/or acceleration synchronised with voltage across the switching device.
• Fast communication allows continuously sending the exact desired opening/closing instant to the motion control.
• the desired instant is thus updated even after the contact part motion has started, allowing more accurate prediction and thus improved synchronisation.
• information regarding events and failures are stored in an event/failure log.
• characteristic parameters from operations are stored in an operations log.
• parameters for the contact parts position, speed and acceleration, the rotor position, speed and/or acceleration, the energy required for operation and the temperature in the switching device during operation are stored in the operations log.
• parameters for the voltage across and current through the switching device during operations are stored in the operations log.
• detailed data from the last switching device operation are stored in a last-operation log.
• the contact parts position, speed and/or acceleration, the rotor position, speed and/or acceleration, the energy required for operation and the temperature during the last operation are stored as functions of time in the last-operation log.
• voltage across and current through the switching device during the last operation are stored as functions of time in the last-operation log.
• a meth- od specified in the preamble of claim 17 includes the steps specified in the characterising portion of that claim.
• the use of an electric motor for operating the mobile contact part makes such tests very easy and reliable to perform.
• the tests contribute to attain an accurate control since it can be based on information from the tests.
• the object of the present invention in a third aspect is to improve a switching device of the known kind of as described above so as to achieve a switching device in which the motion of the mobile contact part is optimised, with respect to timing and motion profile.
• self-diagnostic test is performed on the switching device by making small motor movements.
• the method offers the possibility to supervise the function of the switching device. Since a switching device normally is inactive during its lifetime and operates only during a few short moments there is always a degree of uncertainty whether the switching device is properly ready for operation. By initiating a short motor movement sufficient data for evaluating the condition of the switching device is obtained when controlled according to the present invention. By such a test, information is obtained about the function of the rotor positioning system, the function of a converter when such is present, the function of the motor, the function of the contact parts, the capacity of the electrical storage means, etc.
• the small movement is only a fraction of a full breaking movement, which means less than a 10 th thereof or even less than a 20 th thereof and typically in the range of a few millimetres for a switching device operating on a medium or a high voltage system.
• the contact parts thus are never separated during these tests.
• self-diagnostic test is performed on storage means for storage of electrical energy for the breaking operation by slightly charging or discharging said storage means. Advantage is taken of the possibility offered by the invented method to also check the condition of the electric storage means. Data obtained by this slight charging or discharging informs whether the storage means is ready for operation.
• Self-diagnostic test may be performed either as a result of an external order or as a result of triggering by an internal condition.
• the tests according to the embodiments described closest above and other similar tests, which the present invention makes possible, are advantageously initiated by external order. Such orders are given when it is considered relevant to check the status or are given at regular intervals. In the latter case ordering is performed automatically. Another advantageous alternative is to initiate such tests in response to internal conditions of the switching device. In such a case the tests are automatically performed when internal conditions indicate that there might be risk for defective performance.
• These two advantageous alternatives for initiating tests therefore represents further embodiments of the invention. It is to be understood that the embodiments not only are alternatives. The embodiments can also be combined.
• a processor is used for processing obtained information and/or providing relevant instructions. The processor operates according to a computer program. Thereby control and regulation is performed with optimised efficiency.
• the switching device is small in size and cheap to manufacture.
• the embodiment also makes it easy to amend the way in which control is performed in response to obtained information.
• control means is control means for adaptive control of position, speed and/or acceleration of the at least one contact part during operation in real-time.
• the switching device according to the present invention comprises record means for obtaining position, speed and/or acceleration of contact parts from rotor position, speed and/or acceleration.
• the switching device according to the present invention comprises control means for control of position, speed and/or acceleration of contact parts from rotor position, speed and/or acceleration.
• means for storage of electrical energy is a capacitor bank and/or a battery.
• the switching device comprises means for control of position, speed and acceleration of contact parts during operation in accordance with the specific current to be interrupt.
• control means is arranged to obtain separation of contact parts at breaking operation synchronised with zero crossing of current through the switching device.
• control means is arranged to obtain contact part meeting at closing operation synchronised with voltage across the switching device.
• switching device comprises means for logging and storing characteristic parameters from operations in an operations log.
• said parameters include parameters for the contact parts position, speed and/or acceleration, the rotor position, speed and/or acceleration, the energy required for operation and the temperature during operation in the operations log.
• said parameters include parameters for the voltage across and current through the switching device during operations in the operations log.
• the switching device comprises means for logging and storing detailed data from last switching device operation in a last- operations log.
• the switching device comprises a converter
• said data include data as functions of time and being related to the contact parts position, speed and acceleration, the rotor position, speed and acceleration, the operation of converter, the energy required for operation and the temperature in the switching device.
• said data include data for the voltage across and current through the switching device during the last operation as functions of time.
• the switching device comprises means for storing data for the voltage across and the current through the switching device between and during operations in a long-time log.
• Yet another embodiment of the switching device includes a processor and a computer program product.
• the processor is arranged to process information related to the switching device and/or provides instructions to the switching device.
• the processor operates according to the computer program of a computer program product. Providing the switching device with these components makes it easy to perform the control, and the size and cost for the switching device are reduced. The control process can easily be modified by amendments to the computer program.
• the preferred embodiments of the switching device are specified in the claims depending from claim 21.
• a switching device of the kind specified in the preamble of claim 37 includes the specific features specified in the characterising portion of the claim.
• Preferred embodiments of a switching device according to the fourth aspect of the invention are specified in the claims depending from claim 37. These embodiments offer advantages of similar kinds as those of the preferred embodiments of the corresponding invented method.
• the invention in a fifth and a sixth aspect of the invention, it relates to a computer program product, and a computer readable medium respectively.
• the computer program product and the computer readable medium include the invented computer program.
• the invented computer program includes instructions for a processor to perform the method specified in claim 16, and/or is to be used in a switching device as specified in claim 36.
• the invented computer program product and the invented computer readable medium represent different aspects of a vital component for performing the method of claim 16. As a consequence, they also represent a vital component of the switching device specified in claim 36.
• Figure 1 shows the principle of an electric switching device.
• Figure 2 shows a first embodiment of the actuating means of a switching device of a kind similar to that described in connection with fig. 1.
• Figure 3 shows a block diagram of a switching device according to the present invention.
• Fig. 1 schematically illustrates the principle of an electric switching device. It consists of a breaking chamber 1 , actuating means 2 and an actuating rod 3.
• a breaking chamber In the breaking chamber there is provided a stationary contact part 4 and a mobile contact part 5.
• Each contact part is connected to a conduct respectively.
• the two contact parts 4, 5 are in contact with each other and current flows from the one contact part to the other through the switching device.
• the mobile contact part 5 moves away from the stationary contact part at high speed. Thereby initially an electric arc develops between the contact parts, which arc is extinguished shortly after contact part separation by means of an insulation gas.
• the actuating means includes an electric motor 6 comprising a stator 12 and a rotor 13 enclosed by a hood 7.
• One end of the hood 7 is attached to a mounting plate 8, which is carried by a support, e.g. by means of bolts through borings 9 in the plate 8.
• a post 9 of insulating material e.g. porcelain extends upwards in the figure.
• the insulation post 9 is provided with flanges 10 on its exterior to attain an increased creep distance.
• the actuating rod is arranged inside the insulation post.
• the breaking chamber is housed and its mobile contact part is rigidly connected to the actuating rod 3.
• the actuating rod 3, the insulation rod and the motor 6 are all coaxial.
• a motion transforming mechanism is provided for transforming the rotary motion of motor rotor 13 to translatory motions of the actuating the rod 3 in order to open or close the switching device in accordance with what has been described in connection to fig. 1.
• the motion transforming mechanism will be described more in detail in the following.
• the rotor 13 of the motor is joumalled by a bearing 14,15 at each end of the rotor.
• the stator 12 of the motor is attached to the motor casing 1 and the motor housing in attached to the mounting plate 8.
• the rotor 13 has a central axial boring 30 extending along the major part of the rotor length.
• the mounting plate 8 has an opening coaxial with the motor shaft in which opening a nut 16 is joumalled for rotation in a double acting angular contact ball bearing 18.
• the outer ring 19 of the bearing 18 is attached to the mounting plate 8 by bolds, not shown, in borings 20 extending through a flange on the outer ring.
• An inner ring 21 of the bearing is rigidly connected to a nut 16.
• the inner ring 21 is also rigidly connected to the rotor 13.
• a screw 17 extends through the nut, i.e. a rod having threads.
• the threads of the nut 16 and the screw 17 co-operate in engagement with each other. Relative rotation between them thus results in that the screw is axially displaced in relation to the nut.
• the end of the screw 17 that is remote from the motor, i.e. the upper end in the figure is connected to the actuating rod 3 of the switching device. This is accomplished in that the upper end of the screw extends into a boring 23 in the lower end 24 of the actuating rod.
• the connection is received by diametrically arranged pin 25 extending through the ends of the screw and the actuating rod.
• a guiding sleeve 26 extends enclosing the screw 17.
• the guiding sleeve has diametrically located axially extending guide tracks 27.
• the pin 25 extends out through each guide track 27 and is provided with a locking washer 28 at each end.
• the guiding track 27 has a width corresponding to the diameter of the pin 25.
• the screw 17 is secured against rotation in relation to the guiding sleeve 26.
• the guiding sleeve 26 also is secured against rotation in that it is attached to the mounting plate 8 by means of not shown bolts through the borings 29.
• the guiding sleeve 26 has an inner diameter such that the actuating rod 3 with small clearance is inserted therein.
• FIG. 2 shows the switching device in its normal position when it is in closing position.
• the switching device When the switching device is to be activated to interrupt the current the motor is started so that its rotor 13 starts to rotate clockwise as seen from above in the figure. This forces the screw to move clockwise where through the mobile contact part 5 (see fig. 1) is withdrawn from contact with the stationary contact part.
• the central boring 30 has a length giving space enough for the screw to be displaced a sufficient distance for completing breaking. During the breaking operation the lower part of the actuating rod will slide downwards in the guiding sleeve 26.
• Fig. 3 is a block diagram showing an example of a switching device according to the present invention. It comprises a breaking chamber 1 with contact parts 4, 5. The switching device operates on a line 51 of an electric network, and each contact part 4, 5 is connected to a respective part of the line 51.
• One of the contact parts is mobile and is mechanically connected to an electric motor 6 through a mechanical coupling device 41 for transforming rotary motion of the electric motor to translatory motion of the mobile contact part 5.
• the arrangement of the breaking chamber, the mechanical coupling device and the electric motor can be as illustrated in figures 1 and 2, but other arrangements can be used of course.
• the electric motor 6 is connected by an electric coupling 52 to a converter
• the converter 47 is connected by an electric coupling 53 to a capacitor bank 44. Electric energy for operating the switching device is supplied from the capacitor bank 44 to the converter 47. The converter converts the electricity and supplies it to the electric motor 6.
• the capacitor bank is charged by a charger 48 connected to a network supply 49 or a battery supply 50.
• a control unit 43 controls the operation of the switching device.
• the control unit is arranged to obtain information related to the switching device and to provide control signals for its operation.
• a plurality of signal lines thus connects the control unit 43 with other parts of the switching device.
• a first signal line connects the control unit with a record means 42 in the electric motor 6.
• the record means 42 is connected to the rotor of the electric motor to obtain data about its motion. These data can be position, speed or acceleration or a combination thereof. Since the movement of the rotor is transferred to the mobile contact part 5, the data of the rotor motion are indicative of the corresponding data of the mobile contact part 5.
• the control unit 55 sends control signals to the converter 47, for controlling the operation of the electric motor 6.
• the converter 47 governs the motion of the electric rotor such as its position, speed and/or acceleration, and thereby the corresponding motion of the mobile contact part 5.
• the control signals are produced in response to the signals obtained from the record means 42 through the first signal line 54.
• a storage means 70 is provided. In this storage means 70, measurements and events related to the switching device is logged and stored.
• a third signal line 56 connects the control unit 43 with a measuring unit 57 in the line 51 , on which the switching device operates.
• the measuring unit is arranged to measure the current in line 51 and the voltage across the switching device. Information on these measurements is sent to the control unit 43 through the signal line 56. This information also affects the control signals from the control unit 43 to the converter 47 and therethrough the operation of the switching device.
• the information signals from the measuring unit 57 are also used to synchronise the operation of the switching device with the current and/or the voltage.
• the switching device can be synchronised so that contact part separation occurs at zero crossing of the current or at a predetermined time relation to zero crossing.
• the switching device can be synchronised so that contact part meeting occurs at a predetermined moment in the voltage cycle.
• Further inputs to the control unit are formed by fourth 67, fifth 58, sixth 59 and seventh 60 signal lines from various components of the switching device.
• fourth signal line 67 signals are received from a current measuring unit 45 in the electric coupling 52 between the converter 47 and the electric motor.
• fifth signal line 58 signals are received from the converter 47, which signals are representative of conditions in the converter, e.g. its temperature.
• sixth signal line 59 signals are received from a voltage measuring unit 46 in the electric coupling 53 between the capacitor battery 44 and the converter 47.
• the seventh signal line 60 signals are received from the charger 48.
• the storage means includes a plurality of logs, namely an operations log, an event/failure log, a last- operation log and a long-time log.
• the logs thus contain information on measurements, events and failures in the switching device and include operation parameters, such as contact parts position, speed and acceleration, rotor position, speed and acceleration, energy required for operation, temperature in the switching device during operation, voltage across and current through the switching device, data from the converter.
• the switching device is further provided with a processor 71 , operating according to a computer program of a computer program product such as a computer readable medium.
• the computer program provides instructions to the processor 71 on how the information obtained from the different sources via the signal lines is to be processed in order to create control signals from the control unit 43 for the operation of the switching device.
• the program also provides instructions on how the stored information affects the processing.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Control Of Electric Motors In General (AREA)
• Eye Examination Apparatus (AREA)
• Seal Device For Vehicle (AREA)
• Vehicle Body Suspensions (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Keying Circuit Devices (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
• Massaging Devices (AREA)
• Valve Device For Special Equipments (AREA)
• Iron Core Of Rotating Electric Machines (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20281102

Family Applications (1)

Country Status (8)

Cited By (4)

Families Citing this family (2)

Citations (5)

• 2000
  • 2000-09-18 SE SE0003371A patent/SE520438C2/sv not_active IP Right Cessation
• 2001
  • 2001-09-17 AT AT01965815T patent/ATE392002T1/de not_active IP Right Cessation
  • 2001-09-17 EP EP01965815A patent/EP1334500B1/en not_active Expired - Lifetime
  • 2001-09-17 DE DE60133573T patent/DE60133573T2/de not_active Expired - Lifetime
  • 2001-09-17 CN CNB018190103A patent/CN100477052C/zh not_active Expired - Lifetime
  • 2001-09-17 AU AU2001286373A patent/AU2001286373A1/en not_active Abandoned
  • 2001-09-17 WO PCT/SE2001/001985 patent/WO2002023571A1/en active Application Filing
  • 2001-09-17 JP JP2002527527A patent/JP2004509435A/ja not_active Withdrawn

Patent Citations (5)

Also Published As

Similar Documents

Legal Events