DE2365793A1 - MEASURING VALUE RECORDERS AND CONVERTERS FOR CURRENT IN POWER SUPPLY LINES - Google Patents

Description

2355733

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TOKYO DENRYOKU KABUSHIKI KAISHA, Tokyo, Japan

Measurement transducers and converters for currents in power supply lines

(Removed from P 23 44 921.0)

The invention relates to a transducer and converter for electrical currents in power supply lines, the generates analog measured values for the instantaneous values of the conductor currents and transmits them to the output in digital form.

Electrical power supply networks contain lines and electrical systems that are located at certain points. To monitor and control such power supply networks, transducers are required that are connected to different Places are connected to the supply network in order to generate temporally variable analog signals, such as currents and voltages to be taken from the network and to feed corresponding systems for monitoring and control in analog form.

Since the energy supply networks are becoming more extensive and complicated are being set up, mistakes in the conventional monitoring and control systems make themselves more severe and more serious noticeable. These errors stem, among other things, from the required

2365733

High-voltage connections of the transducers and the complicated construction of the current transformers, others The causes of these errors are, for example, unavoidable errors in the current data that fluctuates over time and due to limited reliability in processing the analog data. To ensure the reliability of such monitoring and To increase control systems, monitoring by means of digital devices is necessary. It then turns out as advantageous, see Stamnian registration P 23 44 921 of the same Applicant, the conversion of the analog measurement data into digital data directly at the point of the transducer to undertake. For this purpose, e.g. synchronously controlled encoders can be provided.

The object of the invention is to provide a transducer for Specify measurement of currents in energy supply networks, which generates analog measured values for the instantaneous values of the conductor currents and is reliable and digital at the output submits without translation errors.

This object is achieved in that a porcelain rod. Current transformer it is provided that the conductor carrying current represents the primary winding of the current transformer and in the tip of the porcelain rod is passed through a secondary winding, and that an encoder in the base of the current transformer is arranged, receives the analog measurement data from the secondary winding and converts it into digital data implements.

Further advantageous forms of embodiment are characterized in the features of the subclaims.

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An embodiment of the invention is described below by way of example with reference to the drawings.

Figs. 1A and 1B show together when Fig. 1B to the right Side of Fig. 1A is applied, the circuit of a conventional system for monitoring and Regulation of electrical power supply networks;

2A and 2B show, when FIG. 2B is applied to the lower edge of FIG. 2A, a perspective illustration a conventional plant

Fig. 3 shows a schematic side view of a transducer known type;

Fig. 4 shows a block diagram of a possible monitoring and control system in which the transducer according to the invention is used

FIGS. 5A and 5B, when FIG. 5B is applied to the right side of FIG. 5A, schematically show the circuit a monitoring and control device in an electrical system shown in FIG. 4;

Fig. 6 shows a block diagram of a synchronized encoder used in the invention;

Fig. 7 shows a side view of a Messwertauf taker and converter according to the invention.

Before describing the system for monitoring and regulating electrical power supply networks according to the invention first a conventional monitoring and control system in connection to be described with FIGS. 1 to 3 in order to facilitate the understanding of the invention.

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In Fig. 1, an electrical system contains, for example, several busbars SA, a first group of isolating switches LSI of a line LI connected to the busbars SA, in connection with the isolating switches LS1, a first group of high-performance switches CBl, a second group of. Disconnectors LS2 between the high-performance switches CB1 and an adjacent electrical installation (not shown), a third group of disconnectors LS3 connected to the busbars SA, a second group of high-performance switches CB2 connected to the third group of disconnectors LS3 and a high-voltage side with The main transformer MTr connected to the second group of high-performance switches CB2, which is connected on the low-voltage side to a generator of the electrical system (not shown) or to an adjacent electrical system or via a further group of high-performance switches (not shown) to the load. A conventional monitoring and control system according to ⁴ Fig. 1 contains a first group of voltage converters or voltage dividers PD1 for measuring the time-variable voltage values of the busbars SA »a second group of voltage dividers PD2 for measuring the time-variable voltage fourth on the line» a first group of current transformers or current transformers CTl for measuring the time-varying current values on the line LI, a second and a third group of current transformers CT2 and CT3 for measuring the time-varying current values on the low-voltage and on the high-voltage side of the transformer MTr.

In Figs. 1 and 2 contains the. » conventional system in addition to the protective devices, transmission devices and similar devices in the relay room 21 of the electrical system and monitoring and control panels in the control room 22 of the system. The Sic-icxle measured by the measuring transducers and corresponding to the time-varying analog data as well as the state of the electrical devices are transmitted via appropriate cables

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The second type of stationary data characterizing the electrical system under consideration is supplied to the relay room 21. The protective devices contain a busbar protection 25 > that on the flute data of the busbar, on the current data of the line and is responsive to the high voltage side power data and a. Sacnel rail protection output signal and a Sanmel rail protection data signal generated; it contains a line protection 2.6, which is based on the line voltage and current data and also on the in a manner to be described yet from the neighboring system connected to the line LI responds to data supplied to ^ rnid ein Line protection output signal and a line protection data signal generated; it contains a line protection in a similar way for the electrical system branching off from the SA dsr busbars Lines (not shown); it contains a line emergency protection device 27, which is based on the Lsitungsspannungs- and current data responds and generates a line emergency protection output signal and a line emergency protection data signal; it contains one Transformer protection 28, which is based on the voltage data of the busbar and responds to the high-voltage and low-voltage side current data and a transformer protection output signal and provides a transformer protection data signal; it also contains a device 29 for automatic error elimination, on the voltage data of the busbar, on the voltage and Current data of the line, on the high-voltage side current data, responds to the stationary network data and to various protection signals supplied by the protection devices 25 to 28 and generates an error elimination output. The protection and fault elimination output signals are grounded electrical devices of the other kind via cables (not shown) supplied to regulate this. The Ufeerv control panels included by the respective electrical systems monitoring and control devices 30, which are based on the voltage data of the busbars, the voltage and current ca ^ en of the line, the high voltage side Electricity data, the stationary network data,

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protection data and from neighboring electrical systems responds to delivered data, and generates status signals that correspond to the time-varying analog data and the stationary Network data of the Saznmelschienen SA and the illustrated electrical Devices. The respective monitoring and control facilities correspond in principle directly to the lines and the electrical devices of the first type of the respective electrical System.

The transmission devices contain high-speed transmission devices 31 and 3 ^ for the transmission of the line protection data signals between the considered and the neighboring electrical systems by means of a microwave converter-receiver section 35, they contain slow transmission devices 36 and 39 for the transmission of the status signals between the respective and the neighboring electrical systems by means of a transmitter / receiver section 35, a further distant sending device if1 for the transmission of the respective status signals to another, further distant sending device ^ 5 »which is located in a central station if6, the similar, further distant sendin * · Direction (not shown) for other electrical systems of the supply network and also contains a remote monitoring and control device Wl .

Each of the voltage dividers PD and the current transformers CT of the Conventional monitoring and control system must have an output signal output high performance, because the protection and monitoring devices and the display devices contained therein have a considerable power requirement, and because the output signals should not be adversely affected by noise during their transmission. To get high power output signals, every current transformer CT must have a core of high magnetic

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Have permeability. With the first stream that a given Exceeds the value, the core reaches its saturation magnetization, which changes into the residual magnetization when a large current through the primary winding is switched off in a very short time, e.g. in the event of a short circuit. By this property of the core, the reliability of the time-varying stream data is deteriorated. Even if very large kernels are used to reduce the magnetic flux density in order to avoid saturation, it is difficult in practice to To reduce the error that occurs with large currents, because the current flowing due to a network disturbance is a factor of several Orders of magnitude greater than normal current values «The cables for the data must be able to handle the output signals to transmit with high performance. In an electrical system with-275kV, the nominal current in the secondary winding is each Current transformer 1 A instead of the unrealistic nominal current from 5A. In an electrical system with 500 kV is each cable is about twice as long as in a 275 kV system and therefore twice as thick because a reduction in the Nominal current below 1 A due to the increased output voltage and the correspondingly increased R aun.be dar fs c, er transducer, the cables and the monitoring and control equipment insulation problems would raise. The required, reliable Operation of the monitoring and control system has an increase in the cable length and the number of relays and increased complexity result in data processing. Regarding the cable length, it is desirable to eliminate the error in the time-varying. Reduce analcg data to below par and to provide the saturation characteristic for exceptionally large values. For a protective relay, the error must be at exceptionally large values that the data assume in the event of a fault. For this reason it is imperative to a variable transformer CT with several secondary v / indun ^ ea when using mi '; various measuring devices and Insert relay. This determines the number and structure of the

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Current transformers more extensive and accordingly also the Number of cables for data transmission, although reliability is not improved. The increased complexity of data processing leads to an increase in the number of errors that occur when analog data is being routed. This fact means a limitation of the reliability of the monitoring and control system. Eei complicated α, just about a few electrical Monitoring and control systems which extend to systems often cause a disruption in the supply network, which is often considerably disadvantageous Effects in the energy supply. In an improved, conventional monitoring and control system for one large expansion area of the supply network, however, the mode of operation is inadequate because of the differences in the errors, with which the analog data are provided in different areas of the supply network, and the resulting large Errors in the entire, large-scale protection area. Also suitable the analog data cannot be saved and can only be done with hardware are processed. Because of this fact, every time there is a change in the supply network, a new one Mode of operation is required for various functions, new devices and new protective devices in the monitoring and control systems Sail system can be installed.

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transformer CTfihehrere 'secondary windings 51 to 55, which are wound on »cylindrical cores located in the base of a perpendicular porcelain insulator 56. The Prinärv / indung 57 consists of a conductor of the line LI and geleitfit through the porcelain insulator% and thereby passed through the zylinderförrnigen cores. The secondary connections. 51 to 55 represent a total of several current transformers.

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The first group of current transformers CDI contains five independent current _{transformers for each conductor of the line LI:} transformers for the protection and monitoring devices; 25, 26, 27, 29 and 30, the second group of current transformers CD2 contains four independent current transformers for the protection / and .., .. / monitoring devices 25, 28, .29 and .30 for each conductor of the transformer MTr. As FqIge- ·. the-. -, _ .. increased number of current transformers, it is necessary for the first and second group of current transformers. -. CTI and CT2 use nine and six four-core cables, respectively. , ..Λ

4 shows an electrical supply network together with the monitoring and control system according to this invention. The supply network contains three electrical systems EHI, EH2 and EH3 and lines LI which "connect the electrical systems EH1, EH2 and EK3 to one another The monitoring and control system contains in each of the electrical systems.EH1 to ΣΗ3 · Monitoring and control devices SC and microwave channels.-CH, which connect the neighboring monitoring and control devices - .. SC with one another. ■ '- ".." - ,; λ.v "" ■ .- · '■ · ".' · - * · -.-: - ■ '> ■ -'ν- : - /. ^ - λΓ ,." _: "■ * -. .. .Ιντ

In Fig. 5 pra-8 (one in Fig.: ^ Nurscheraatiscb. Indicated;, _<: - _: given monitoring and control device SC is shown in more detail. The monitoring and control device SC contains a control oscillator 60 for Generation of clock pulses, a first synchronized encoder 6j for the first voltage divider PD1, a second synchronized encoder 62 for the second voltage divider PD2, a third synchronized encoder 63 for the first group of current transformers CT1 and a fourth synchronized encoder Sh- for the second and third group of current transformers CT2 and CT3 The synchronized encoders 61 to 6 * t key simultaneously in time with the clock pulses

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an al ο ι; · :; η data from the supply network through the corresponding - '. ^ iy.vertaufnehnier were taken, and put the palpated analog; converts data into digitally coded signals. For this purpose contains j odor synchronized coders according to Fig / Synchronizer 66 to the supplied clock pulses accordingly to delay the desired phase delay of the clock pulses. In addition, this should correspond to the time-changing data Signal can be sampled at ten to twenty times the frequency of the normal mains frequency, thereby increasing reproducibility enable. The frequency of the clock pulses is accordingly 1200 Hz.

• The — vGs — S ^^ tter-o & säü-afeor-60— generated pulse pulses should be represented according to FIG. 3 (a) by S1, SZ , ..., unc

have the period T _Q. As shown in FIG. 8 (b), the clock pulses reach the Kodi'er with a time delay T ₁ . The synchronizer 66 delays the received. Clock pulses with a time T = T - T ₁ , so that the analog ^ data is synchronous with

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gated the clock pulses generated in the control oscillator 60, v / ie shown in Fig. 8 (c). The source oscillator 60 can be built into one of the encoders 61 - 6 ^ -. The control oscillator 60 can, however, also be installed at a point that is further away be. In this case it may be necessary to adjust the delay time

.T ₀ to give the expression of the difference ηΤΐ-Τ, where η is a positive, a jS ο ι

means whole number. Each encoder also contains a sampling circuit 67 which samples the analog data signals in accordance with the delayed clock pulses supplied, it contains an analog-to-digital converter 68 for converting the sampled analog signals into digitally encoded signals and it preferably contains a bipolar converter. 69. ⁷ -v ,: v Conversion of digital signals into bipolar coded, digital SigusLe. For several analog data

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ga een eder electrical systems is controlled by the Uberrachungs- und'Regelcinheit 106 of the central station from together kit "of the input output gate unit 105, the slow center wheel spoke 102, the Transmission unit 111 and one of the modulator-demodulators 112, 113 ... executed. Ία. e of the monitoring and control unit 1Oo and / or the storage unit 10? v / ground out confused data in the same way the ent speaker.do η units in the electrical

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and control system — ftaeh — aleserfindungg It is a porcelain converter, one vertical for each conductor of the line LI. Porcelain insulator 56 and in the top of this porcelain insulator 56 only contains a single secondary winding 115, and which also contains one synchronized encoder 116 in the foot of the porcelain insulator 156 has. The primary application 57 consists e.g. of only one ' rectilinear conductor of the line LI, which is passed through the secondary winding 115. In contrast to current transformers, more conventional The design of the current transformer CD does not contain a core made of magnetic material.

Thanks to the synchronized encoder, each of which in addition to at least one to extract the time-varying analog. If a suitable transducer is attached to the data, it is possible within the scope of this invention to process even weak analog signals for various monitoring and control processes. For this reason, a current transformer and small voltage dividers constructed according to Fig. M \ can be used, and the number of current transformers can also be reduced, as can the number and size of the cables for the current data. In one example, the total copper

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weight for a monitoring and control device according to this invention 0.1} t compared to approximately 16 t for a monitoring and control system of conventional design. The basis was a typical system with twelve lines and eight transformers · This fact also simplifies the installation of a "monitoring and control system." - · '' · - ■ ^{T l} . · ^

When using the "'It is because there is no iron core is used not erforderlieh to consider the failure of the transmission ratio is thereby the reliability of überwächürigs- and Regelan-i. ^■:"' in FIG Vf shown ^ Stro ^ fepansiöpiiiartors. Location in the case of a simplified embodiment, the conductors of the line LI can also be kept shorter, since the secondary winding is in the tip of the porcelain rod.

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Temporally variable analog data makes it possible to implement a reliable, high quality monitoring and control system because of the simplicity with which the signals disturbed by unavoidable noise can be returned to a processable pulse form. The monitoring and control system works At high speed, because it is easy to detect and correct faults in the network in a short time, and because it is superfluous to monitor the data for the detection of a fault over a long period of time. By means of time synchronization, the data processing is considerably simplified and the device units are reduced in size. Without the corresponding synchronization, more complex data processing devices would be required. The combination of the digital data processing units with the synchronized encoders allows the data processing units to be used in a variety of ways by means of appropriate programs; Thus, the Uberwachungs- / and control system are increased reliability, versatility and economy. One of the invention from gegTfg € tn ^ ^ igoearaniage

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Claims (4)

2355793 Claims Measured value recorders and converters for electrical currents in power supply lines, the instantaneous values the conductor currents generate analog measured values and send them to the output in digital form, characterized in that a porcelain rod current transformer (CT) is provided is that the conductor current carrying conductor (57) represents the primary winding of the current transformer (56) and passed through a secondary winding (115) in the tip of the porcelain rod (56) is, and that an encoder (116) is arranged in the base of the current transformer (56) of the secondary winding (115) receives the analog measurement data and converts it into digital data. 2. transducer and converter according to claim 1, characterized in that that the conductor (57) is passed in a straight line without a loop through the secondary winding (115). 3. transducer and converter according to claim 1 or 2, characterized in that that the secondary winding (115) is constructed without a core. 4. transducer and converter according to one of the preceding Expectations, characterized, 609820/0404 that the encoder (116) from a centrally located Main oscillator (60) is controllable and is synchronous with other measured values on sensors that correspond to the instantaneous values of the phase currents digital Submits data. ReRb / Pi. 609820/0404 Blank