DE1945802C3 - Circuit arrangement for the automatic, optional connection of a single measuring device to one of several measured variables - Google Patents

Description

Delay stage (V) given time period a This object is inventively geVerriegelung all selection gates (Ga 1 to 60 resolves that the excitation circuit comprises a gate-arrange- GAII) of all the static switch is nune connected by locks whose individual selection (5 / 1, 5/3; SmI, Sm3) for a further, pre-gate for determining the time period given to the measuring device. measured quantities to be connected to each

7. Circuit arrangement connected to one of the different outputs of the excitation circuit 2 to 6, characterized in that between 65 are and that the selection gate is used the gate arrangement (G) and the statically controlled, static switch are provided through which see switches (S / 1, 5/3; SmI, Sm3) a Pro- the measuring device to the selected measuring program circuit, preferably a large diode matrix can be connected.

The circuit arrangement according to the invention is of particular importance for multiphase distance protection with a single distance and direction measuring device. In known distance protection devices with a single distance and direction measuring device, relays controlled by overcurrent or underimpedance relays were used, which select only a pair corresponding to the respective fault case from the measured variables of the multi-phase network to be monitored and feed them to the distance and direction measuring mechanism via their contacts . Several (mostly) changeover contacts are always connected in series. The naturally not simultaneous closing or switching of the contacts of the relays remains without serious impairment of the measuring properties if a sufficient period of time is available for the subsequent measuring device to make a decision. B ^p i the known distance Schulz devices, in which the measuring device consists of a rectifier bridge circuit with moving coil relay, the required period of time is available from the outset, since these distance protection devices have a relatively long decision time.

However, new distance protection devices with static measuring devices have relatively short decision times on. Such transistorized measuring devices can already be in considerably less than make a decision within a period of the network frequency after switching on the measured variable. To with such Distance protection devices the influence of the circuit arrangement for optional connection to individual To reduce measured variables with regard to the total decision time of the device, one has the Relays already designed as protective gas contact relays, the contacts of which work almost bounce-free. A simultaneous one Switching of all the contacts involved cannot, however, even using such relays always be achieved, so that artificially time-delaying measures are taken in an undesirable manner must, whereby a possible shortening of the command time cannot be achieved.

In this regard, according to a further development of the. Invention advantageously short decision times for distance protection devices with one at one Faults in the multiphase network to be monitored, pickup signals characteristic of the respective fault Achieve emitting excitation circuit when the excitation signals are intended for the respective fault Unlock the selection gate of the gate arrangement and through the subordinate to the selection? -Oattern static switch a connection of the distance and direction measuring device to the respective Measured variables characterizing errors that have occurred are carried out.

It has proven to be advantageous if a Connect the distance and direction measuring device to the respectively selected measured variables the static switch takes place only after a period of time predetermined by a delay stage. In the case of multipole errors, it is to be expected that the excitation signals from the excitation circuit not be submitted at the same time; in order to avoid an incorrect selection caused by this, with connecting the distance and direction measuring equipment using the delay stage waited for a predetermined period of time, for which about 5 ms are generally sufficient. Through this it is achieved that the selection gates only send a pulse as a control signal to downstream static switch can be issued if with certainty in the event of an error of der., activation circuit all characterizing this error Signals have been delivered to the gate arrangement. This training of the invention Circuits is of course also for

ίο fast auxiliary relay selection circuits appropriate.

The one causing a fixed, predetermined time delay Delay stage is advantageously connected to the excitation circuit and is through brought at least one (first) excitation signal to start.

As already briefly indicated above, the gate arrangement includes the one to be monitored for every fault Multi-phase network provided a selection gate. To be sure of an incorrect selection with To avoid triggering an incorrect static switch, this occurs as a result of an error Unlocking the respectively assigned selection gate via auxiliary gate locking the remaining selection gate. This, in cooperation with the delay stage, ensures that only from the selection gate a control signal is output to downstream static switches, which deTi actually assigned errors that occurred in each case is.

It has proven to be advantageous if in the circuit arrangement according to the invention in one Error change after the time period given by the delay stage has elapsed all selection gates with blocking of all static switches for a further, predetermined period of time he follows. A duration of around 10 ms has proven to be sufficient. It will then be the connected static switch is blocked again, and only then are the corresponding Selection gate released for selection.

It has also proven to be useful if

a program circuit, preferably one, between the gate arrangement and the static switches Diode matrix, is arranged, which is designed for a phase preference.

The circuit arrangement according to the invention has proven to be used as a static switch Full-wave thyristors (triacs) proved to be useful.

To explain the invention, FIG. 1 shows an exemplary embodiment of the circuit arrangement according to the invention, for the sake of clarity, with only all of the individual parts that are required to detect a two-pole fault in phases R and T; 2 shows the gate arrangement with the diode matrix in the form of a block diagram.

The phase currents Jr, Js and Jt and the neutral current Jm flow to the exemplary embodiment of the circuit arrangement according to the invention shown in FIG. 1 via terminals Kir, Kis, Kit and Kim; The terminals are connected to a star point M via impedances Zr, Zs, Zt and Zm . In parallel to the impedances Zr to Zm , primary windings WpH and Wpi3 of transformers (matching transformers) Γ / Ι and Ti3 are connected. In each case a secondary winding Wj / 11 or Wxi3l of the transformers Ti 1 and Ti3 is with

5 6

their connecting ends Aiii ' and Aiii' or Ai31 'of these lines a fault in one through the last

and / 4/32 'with assigned inputs Aiii " Letters of the line designation marked

AiM " or ΑΊ31", / 1/32 "of an activation circuit AS netcn phase has occurred

connected. Further connections AuIl ", AuM" and Fchler cases in a multi-phase network accordingly

Au3 \ ", Au31" of the excitation circuit AS stand with 5 are with the individual lines Lr to Lm as AND

Terminals AUIL ', AUIL' and Au3l ', Au3T the formed gate select gate Ga 1 to Gail

Secondary windings WiMlI and Wsu 31 connected from afar, with every possible fault

ren transformers (matching transformers) 7m 1, selection gate is assigned.

7'm2 and Tu3 in connection, the primary windings of which, apart from these selection gates, are GaI to GaIl

gen WpMl to Wpu3 to the phase voltage Ur, Us io in the gate arrangement G auxiliary gate G / il to GhI

and Ut are connected. provided, which ensure that when unlocking

Each of the adjustment contributors Γ / 1 and Ti3 result in a selection gate GaI to GaIl all

like TmI to Tu 3 each has an additional Se- remaining selection gate except for the example

Curidary winding Wsill and W «32 as well as Wsull are locked until pre-corrected selection gate Ga 11,

W * m32 on; the secondary windings Wsill and 15 that for the detection of three-pole faults with earth

Wsi 32 are each used with one end of the winding in contact.

connected directly to each other, while their respective to the output line Lr to Lm of the other winding ends via windings Wz 11 and circuit, the delay stage V (see Wz 13 of an intermediate transformer Tzi with each also Fig. I) is connected, which when an anode occurs of static switches 5/1 and 5/3, preferably designed as full-wave thyri ^ o first signal on one of the lines Lr to Lm anstoren, and are reverse connected for a predetermined period of time. The respective other anodes of the stages with amplifier effect (NAND gate) US 1 static switches 5/1 and 5/3 are directly connected to i / 511 in the gate arrangement C? locked and connected to each other and routed to earth. thus preventing a choice. Only after it has expired

The respective second secondary windings * s of the predetermined period of time are also the reversing Wsu 12 to Wsu 32 are released with regard to their one step USl to USIl and thus the winding ends are directly connected to one another; With the transmission of signals from the selection gates at their respective other winding ends, these SeGaI to GaIl to the inputs £ 1 to £ 11 of the secondary windings Wsull to Wsu32 are made possible via the respectively downstream diode matrix DM . With a winding Wz21 and Wz23 of a further intermediate 30 outputs E1 ' to £ 16' of the diode matrix DM, there are schcnüberlragers Tz 1 each with an anode then those in connection with FIG. 6 verbal expander. static switches 5/1 and 5/3 or 5m 1 to formed, static switches Su 1 and 5m 3 connected to each other. The number of printouts shown. The other anode connections of the static switch 5m 1 and 35 separates for distance and direction measuring units of a Su3 are directly connected to each other and also distance protection device, whereby a three-phase network is connected to ground. solidly earthed star points are used as a basis

Secondary windings Wzs 1 or WuI of the intermediate and the direction determination with non-short-circuit

interchangeable transformers 7z 1 and Tz 2 are carried out directly with voltages; for other network vct

the measuring mechanism, not shown in FIG. 1, has a smaller number of outputs

and give the enough at their winding ends.

Occasional error associated, current and voltage occurs, for example, a two-pole error in the

voltage-proportional, measured variables to be evaluated. Phases R and T of the multiphase to be monitored

The activation of the static switches 5/1 and network on, then from the excitation circuit AS Si3 or 5ul and 5m 3 takes place via a program 45 excitation signals on the output lines Lr and Lt circuit in the form of a diode matrix DM, which emits a. The delay stage V starts up and equips the two signals immediately when the first of the two signals occurs. The diode matrix DM is controlled by locking the reversing stages UsI to UsIl. Of one of the selection gates GaI to GaIl, shown only schematically in FIG. 1, the gate Ga S is gate arrangement G, which on the one hand is unlocked by the excitation 50, while all other selection gate interconnection AS is controlled and on the other hand remains locked. After the predetermined Zeil then to release control signals to said diode, therefore, a signal from the selection gate GaS matrix DM is released when a delay to the input given £ 5 of the diode matrix DM treatment stage V, also by the Activation circuit whereby the static switches 5/1 and 5/3 as well as AS is activated, after a predetermined time 55 5m 1 and 5m3 (see. Fig. 1) permeable controlled duration has expired and then a pulse is sent to the. It is then up to the error case RT to c-gate arrangement G gives. associated measuring voltage Jr · Zr + Jt · currently the Wick-

The excitation circuit ASYznn in known lungen WzIl and W ζ 13 of the intermediate transfer TzI

Way in the manner of an overcurrent or underimpulse and that of the short-circuit voltage Urt proportional

danzanregung work. It is therefore not closer to the measured voltage at windings Wz 21 and Wz 23

described. of the transformer 7 "z2. There then occurs an error

To further explain the current-proportional measured variable assigned to RT according to the invention

The circuit arrangement in Fig. 2 is the structure MgI on the secondary winding Wzs 1 of the intermediate

dcr gate arrangement G shown in more detail. One he transformer TzI and thus at an input of the

knows of the excitation 65 measuring mechanism, not shown in FIG. 2; another, the short-circuit voltage

circuit outgoing lines on the output side, the Urt proportional measured variable Mg 2 is at the second

are denoted by Lr, Ls, Lt and Lm , in order to auxiliary winding Wz.f2 of the intermediate transformer 7 ″ z2 and

th that when a potential occurs at one of them at the other input of the measuring mechanism.

1 sheet of drawings

Claims (6)

(DM), is arranged, which has a phase prior Patent claims: g circuit arrangement according to one of the preceding claims, characterized in, 1. Circuit arrangement for automatic, 5 that the static switches (5/1, 5/3; SuI, Su3) optional connection of a single measuring single-wave thyristors (triacs) are,
direction to one of several measurands, in which a measurement-dependent controlled control circuit causes the selection of the individual measured variables, thereby marked io net, that the drive circuit (AS) a The invention relates to a circuit gate array (G) is connected, the arrangement for automatically, selectively Anschlieeinzelne selection gate (GaI to Gail) for ER SEN a single measuring device to individual averaging of the respective measured variables to the measuring device, in which a measured variable dependent measured variable causes the selection of the individual measured variables connected to various 15 gigantic controlled excitation circuits. are, and that via the selection gate (Gill to With advantage ei.ie such a circuit arrangement GnIl) controlled, static switches (5/1, 5/3; are always used when 5m 1, Sm 3) are provided, through which the measurement with the least possible effort by means of device to the selected measuring device 20 use a single measuring device several large can be connected. Measured variables are to be monitored; requirement 2. Circuit arrangement according to claim 1 for it goes without saying that not at the same time a multi-phase distance protection with a one time all measured values to be recorded Distance and direction measuring device, but that at the same point in time in each case in such a way that, in the event of a fault, the activation circuit only evaluates a few of several measured variables ler in the multi-phase network to be monitored for. This is often the case, for example excitation case characteristic of the respective error, if by means of a single measuring device emits signals, characterized in that the several measured variables with regard to the excess or Stimulation signals that monitor the failure of specified measured values in the event of a fault provided selection gates (GaI to GaIl) 30 should be. unlock the gate arrangement (G) and that such a circuit arrangement is already through the selection gates (GaI to GaIl) and the use of relays with corresponding downstream static switch (5/1, 5/3; contacts as Siemens distance protection R 1 Z27 a before-SmI, Sm 3) a connection of the distance and used, the relays by the measurand direction measuring device to the respectively occurring 35 dependent activated activation circuit Measured variables characterizing errors are carried out. the. The relays are by means of their contacts 3. Circuit arrangement according to claim 2, that the individual selected measured variables with the measurement through characterized in that connecting the device connected, so that then the evaluation Distance and direction measuring device can be made on. Difficulties with one However, in each case occurring type of error corresponding to 40 such circuit arrangements occur above all Measured variables by the static switch (5/1, "by bouncing the relay contacts; also er-5/3; SmI, 5m3) after a delay due to the relatively long preparation stage (F) predetermined period of time takes place. Delayed connection during the relay's speaking times 4. Circuit arrangement according to claim 3, that the measuring device is connected to the respectively selected measuring through characterized in that the predetermined 45 large. Delay stage causing time delay The same applies to a known device (V) connected to the excitation circuit (AS) for the excitation of several phases associated with it is and by at least one (first) activation signal selective protection relay and to switch it on is brought to start. which are characteristic for the various error cases 5. Circuit arrangement according to one of the antistatic electrical quantities in Mehrphasensystesprüche 2 to 4, characterized in that at men (German patent 740 449); because in this unlocking of a selection gate (eg GaIl) device, a locking relay with contacts is used for phase selection also via auxiliary gates (GAl to Gh 7). development of the other selection gates (e.g. GaI to The invention is based on the task of Ga 10) takes place. 55 a circuit arrangement of the aforementioned 6. Circuit arrangement according to one of the An Art without relays to avoid bouncing Claims 2 to 5, characterized in that to avoid relay contacts and the response time an error change after the expiry of the to be shortened.