Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
  • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
  • G01R15/22—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-emitting devices, e.g. LED, optocouplers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
  • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
  • G01R15/142—Arrangements for simultaneous measurements of several parameters employing techniques covered by groups G01R15/14 - G01R15/26
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
  • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
  • G01R15/16—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using capacitive devices

Definitions

• the invention relates to a high voltage potential transducer according to the preamble of claim 1.
• Measuring transducers of the type mentioned at the outset are used to detect the voltage and / or the current in a high-voltage switchgear, for. B. in a gas or liquid insulated or outdoor high voltage switchgear.
• capacitive voltage measuring devices are provided in the usual way, which are designed as capacitive voltage dividers and - in principle - from one between the inner conductor and one at a short distance from the inner surface of the outer conductor (metal encapsulation ) and insulated from it there are the high-voltage capacitor located and a low-voltage capacitor, the latter being formed between the measuring layer and the outer conductor.
• the voltage measurement values are recorded on the undervoltage capacitor.
• a measuring transmitter for high-voltage lines has become known, which has operating potential, ie high-voltage potential, measuring transducers for electrical quantities of the high-voltage line.
• the output signals of the transducers are fed to a conversion digitizing part which is at operating potential and are transmitted as digital signals to ground potential, for example, by a transmitter.
• a conversion digitizing part which is at operating potential and are transmitted as digital signals to ground potential, for example, by a transmitter.
• How the transducer is designed cannot be seen from DE-OS 25 46 694.
• one radial bore must be provided in the inner conductor and one in the outer conductor in the case of metal-encapsulated systems.
• the bore in the outer conductor is to be closed by means of a transparent window.
• DE-OS 37 12 190 discloses a measuring arrangement which is at high voltage potential and whose measuring signals are transmitted as light signals to earth potential. What is important, however, is that the energy supply, on the one hand, and the way in which the measurement signals converted into light signals are carried out, in particular, are designed differently in metal-encapsulated systems.
• a transducer unit is thus formed which can be retrofitted in existing systems. Due to the fact that the measuring electrode has an outer diameter which is the same as the outer diameter of the inner conductor, the dielectric strength between the inner conductor in the area of the measuring electrode and the outer conductor does not change if the unit is housed in a metal-encapsulated high-voltage system .
• a measuring arrangement is known from JP Abstract 58-124 960, which is arranged in a semicircular cutout in the inner conductor.
• the sensor is a photo element with which the electrical field inside the recess is detected.
• this takes place in that the cutout in which the sensor is located is flanked by two further cutouts on the opposite side of the inner conductor, as a result of which an omega-shaped or meander-shaped current path is generated.
• the cutouts are inserted so deep that the bottoms of the cutouts lie on the central axis of the inner conductor.
• the light guides are guided in a spiral or meandering shape to the outside through the disk-shaped support insulator to ground potential. This ensures that any creepage distances between the post insulator and the light guides are as long as possible for possible discharges.
• the known insulator is not a disk-shaped support insulator located within a gas-insulated, metal-encapsulated system, but a porcelain insulator with plates for extending the creepage distances.
• the light guides are on the outer surface and they run helically, but not spirally.
• a further embodiment of the invention can be found in claim 4, which indicates how the measuring electrode is held in the recess.
• the so-called measuring coating of the measuring capacitor is kept at a distance within the depression by the thin insulating material webs and that its length is shorter than that of the depression means that the dielectric of the measuring capacitor is essentially the same dielectric is like that inside the metal encapsulation.
• the transmission ratio of the capacitive voltage divider and thus the measuring signals of the measuring capacitor are primarily temperature-independent.
• the measuring coating of the capacitive transducer does not have to extend over the entire circumference of the high-voltage conductor.
• the inner conductor according to claim 5 similarly has a circumferential additional depression, which is covered by a cylinder which adjoins one edge of the depression and ends at a distance from the other edge;
• a coil is preferably arranged, the signals of which can be fed to the transmission circuit arrangement.
• a further embodiment of the invention can be found in the characterizing features of claim 6. Thereafter, a capacitor arrangement is also provided for the voltage supply of the transmission circuit arrangement within the outer surface of the conductor, which arrangement is formed in that the conductor has a circumferential recess in which an electrode insulates at a distance from the bottom of the recess is arranged.
• the outside diameter of the electrode corresponds to the outside diameter of the conductor.
• the voltage picked up by the transducer or the current taken up by the transducer is in itself an analog signal, and accordingly the circuit arrangement is expediently designed as an analog / digital converter with a light transmitter which converts the analog measurement signal into a digital light signal converts which is transmitted by means of the light guide to an evaluation unit located outside the encapsulation.
• the measured values can additionally be transmitted in an analog form with a further light guide section into the outside space to the evaluation unit in order to be able to record the phase angle precisely.
• the transmission circuit arrangement or in short the measuring electronics, is located within the inner conductor and thus at high potential. For technical reasons, for example with high load currents or solar radiation, the temperature of the inner conductor can reach 80 ° C. Temperature rises up to 130 ° C cannot be excluded. The reliable functioning of the transmission circuit arrangement designed as microelectronics and the associated optoelectronics with which the data are converted into light signals is only guaranteed up to limit values for the operating temperature, which are 75 ° C. and in special cases 125 ° C. .
• the entire measuring arrangement ie. H. the transmission circuit arrangements may each be mounted on a Peltier element serving as a cooler, which may be supplied with current by a corresponding current transformer.
• the invention is applicable to all types of systems in which currents and voltages flowing in conductors at high voltage potential are to be measured.
• These systems can be open-air systems or metal-encapsulated, gas or liquid-insulated switchgear.
• Figure 1 is a schematic representation of a capacitive
• FIG. 2 shows a schematic illustration of a current transformer, similar to the illustration according to FIG. 1,
• FIG. 3 shows a combi converter consisting of a current and a voltage converter according to FIGS. 1 and 2, likewise in a schematic representation, and
• Figure 4 shows the transducer of Figure 1 with a Peltier element for cooling.
• a metal-encapsulated, gas-insulated high-voltage switchgear as shown in FIG. 1, has an outer encapsulation 10 located at earth potential, in which a hollow inner conductor 11 located at high voltage potential is arranged concentrically.
• the outer encapsulation 10 is composed of two encapsulation parts 12, 13, at the ends of which a flange 14 or 15 is provided, between which a disk-shaped support insulator 16 for the inner conductor 11 is clamped.
• a number of inner conductors corresponding to the number of phases can of course also be provided in multiphase-encapsulated switchgear.
• the conductor 11 has a first circumferential recess 17, on the bottom of which insulating webs 18 and 19 are arranged, by means of which a measuring coating or a measuring electrode 20 is supported in an insulated manner with respect to the conductor 11.
• a measuring capacitor 21 is thus formed between the measuring coating 20 and the bottom of the recess 17; with the capacitance 22 located between the measuring coating 20 and the encapsulation part 12, the measuring capacitor or capacitance 21 forms a capacitive voltage divider.
• Connection lines 23 and 24 are connected to the measuring pad 20 on the one hand and to the inner surface of the hollow conductor 11, which lead to a circuit arrangement 25 of a transmission circuit arrangement arranged in the interior of the conductor 11, in which the through the conductors 23 and 24 to the circuit arrangement 25, the analog measuring signals of the measuring capacitor 21 are converted into digital signals.
• the circuit arrangement 25 is an analog / digital converter.
• the individual cross sections of the light guide arrangement 27 can be seen in FIG. 1.
• the light guide arrangement 27 is connected to an evaluation circuit 28 in which the light signals are evaluated.
• the converter 25 is supplied with voltage by means of a capacitor arrangement which is similar to the measuring capacitor.
• This capacitor arrangement 29 has a third recess 30, on the bottom of which webs 31 and 32 are applied, which hold a capacitor electrode 33, as a result of which a supply capacitor 34 of this second capacitor arrangement is formed.
• the capacitance located between the electrode 33 and the encapsulation part 10 has the reference number 35.
• the electrode 33 on the one hand and the inner conductor 11 on the other hand are connected to the converter 25 by means of electrical lines 36 and 37.
• Figure 2 shows another embodiment of a transducer.
• a further depression 40 is introduced within the inner conductor 11, which is covered by an edge 41 of the depression protruding toward the outer surface except for a gap 43.
• a coil 45 is accommodated in the interior 44 through the cylinder 42 and the bottom of the depression 40, which coil is designed, for example, as a Rogowski coil and the measurement signals of which are fed to the converter 25.
• the voltage supply for the converter 25 is provided by the capacitor 34 of the capacitive voltage divider 34, 35, which is constructed in the same way as the voltage divider used to supply the voltage to the measuring transducer 21/22 and therefore has the same reference numbers.
• the remaining structural design of the arrangement according to FIG. 2 corresponds to the arrangement according to FIG. 1.
• FIG. 3 shows a combination of the two transducers according to FIGS. 1 and 2.
• This combination has the transducer 50, which corresponds to the current transformer shown in FIG. 2, and the transducer 51, which corresponds to the capacitive transducer according to FIG. 1.
• the supply capacitance 29 is provided, which is to be dimensioned such that it can supply the two converters 52 and 53 evenly with voltage.
• Both the converter 52 with the light transmitter 54 and the converter 53 with the light transmitter 55 emit their light signals to the two light guides 56 and 57, which correspond to the light guide 27 in FIGS. 1 and 2.
• Both light guides 56 and 57 run spirally through the post insulator 16 to an evaluation unit 58 which corresponds to the evaluation circuit 28 in an adapted form.
• An additional light guide is not shown, which is assigned to the capacitive transducer 21 and the inductive transducer 45 and which feeds the signals generated by the respective transducer in analog form to the evaluation circuit.
• These additional light guide arrangements would also be passed spirally through the post insulator 26; With these analog signals, which are in the same phase with the quantity to be measured, the phase angle can be detected precisely.
• the invention can be used in gas- or liquid-insulated metal-encapsulated high-voltage switchgear and in open-air systems, and overall has a comparatively small space requirement and can also be produced with little effort.
• the description of the figures shows only a single conductor within the metal encapsulation; If the high-voltage system is a multi-phase encapsulated system, then the measuring surface of the capacitive measuring transducer, such as that with reference number 20, can only be formed over part of the circumference, so that the voltages of the individual conductors can be measured separately.
• each transducer or supply capacitance contains the same dielectric as inside the outer encapsulation 10, so that the measurement signals are temperature-dependent in a first approximation.
• the cylinder 42 ends at a distance from the next edge of the depression 40, as a result of which the gap 43 is formed. This is very important in order to avoid short-circuit currents which cause magnetic shielding of the coil.
• the cylinder 42 serves only as a shield for the coil 45, whereby measurement errors caused by capacitive interference are avoided.
• the coil 45 is expediently designed as a Rogowski coil.
• Both the capacitive transducer with the voltage supply and the current transformer with the capacitive voltage supply and, moreover, also the combination transformer according to FIG. 3 can be readily prepared and prefabricated as a unit in the factory.
• the fact that the supply of the transducers 25 or 52 and 53 is designed as a voltage supply is due to the fact that voltage is always present or the voltage leads the current. This has the advantage that the supply of the transducers 25, 52 and 53 and the associated light transmitter 26, 54, 55 is always ensured.
• Figure 4 shows a transducer with cooling.
• Peltier element 61 On a shoulder 60 inside the inner conductor 11 a Pel ⁇ tier element, which is designated in its entirety with 61, is placed.
• the Peltier element 61 has conductor materials of different electrical conductivity, as is known, for example, from Meyers Lexicon of Technology and the Exact Natural Sciences, volume 3, page 1916, so that the composition need not be discussed in more detail here.
• the transmission circuit arrangements are or are thermally contacted with the cold surface of the Pelier element 61.
• the Peltier element 61 is supplied with current by means of a suitably dimensioned current transformer 62 surrounding the inner conductor 11 via lines 63 and 64, so that a sufficient cooling effect can be achieved for the transmission circuit arrangement 25/26.
• the power supply 29 could also be used. It goes without saying that a rectifier must be provided and is not shown in more detail in FIG. 4.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6423519

Family Applications (2)

Family Applications After (1)

Country Status (4)

Families Citing this family (9)

Citations (6)

Family Cites Families (9)

• 1991
  • 1991-01-23 DE DE19914101858 patent/DE4101858C1/de not_active Expired - Fee Related
  • 1991-01-23 DE DE19914133508 patent/DE4133508C1/de not_active Expired - Fee Related
• 1992
  • 1992-01-21 WO PCT/EP1992/000114 patent/WO1992013278A1/de not_active Application Discontinuation
  • 1992-01-21 DE DE19924201434 patent/DE4201434A1/de not_active Ceased
  • 1992-01-21 EP EP19920903308 patent/EP0521125A1/de not_active Withdrawn
  • 1992-01-21 EP EP19920905577 patent/EP0521146A1/de not_active Withdrawn
  • 1992-01-21 WO PCT/EP1992/000112 patent/WO1992013279A1/de not_active Application Discontinuation
  • 1992-01-21 JP JP92503477A patent/JPH05508021A/ja active Pending
  • 1992-01-21 JP JP92504886A patent/JPH05508223A/ja active Pending

Patent Citations (6)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events