SE123710C1

SE123710C1 -

Info

Publication number: SE123710C1
Authority: SE
Publication date: 1948-01-01

Description

Uppfinnare: J. Stoeeklin. Inventor: J. Stoeeklin.

Prioritet begard frdn den R8 oklober 1944 (Schweiz). Priority was given to the R8 in October 1944 (Switzerland).

Vid anvandning av ,differentialrelaer som transformatorskydd maste som bekant alga"- der vidtagas for att forhindra, att relaerna vid inkopplingen av transfornaatorn Visa ut pa grand av den okade magnetiseringsstrommen. When using differential relays as transformer protection, as is well known, algae must be taken to prevent the relays from being switched on when connected to the transformer due to the increased excitation current.

De kanda anordningarna faranleda antingen att skyddet sattes ur funktion under inkopplingstiden eller att dess kanslighet fOrsvagas. For detta andamal forses transformatorbrytarna med hjalpkontakter, medelst vilka vid inlaggningen av brytaren den namnda verkan Astadkommes Over hjalpapparater. Naadelarna med denna anordning bestar dari, att vid inkopplingen av transformatorn differentialskyddet är overksamt eller mycket okansligt under viss lid. Dessutom Mir anordningen overksam, om transformatorn vid inlagd egen brytare sattes under spanning Iran natsidan, sa att i detta fall en joke Onskad urkoppling av transformatorn kan intrada. The known devices cause either the protection to be deactivated during the switch-on time or its feasibility to be weakened. For this purpose, the transformer switches are provided with auxiliary contacts, by means of which during the insertion of the switch the said effect is achieved via auxiliary devices. The disadvantages of this device are that when the transformer is switched on, the differential protection is ineffective or very impermeable for a certain period of time. In addition, Mir device inactive, if the transformer at the inserted own circuit breaker was put under voltage Iran night side, said that in this case a joke Unwanted disconnection of the transformer can enter.

Enligt andra kanda metoder anvander man sig av en upptradande likstriimskomposant eller av overtoner i inkopplingsstrammen for blockering av skyddet med tillhj alp av elektriska hjalp- och filterkretsar. Vidare har fareslagits en losning, omfattande en mellan transformatorn och dess brytare inkopplad spanningstransformator, enligt vilken Lill denna spanningstransformator ar anslultet ett nollspanningsrela, som vid sin attraktion for bestamd tid sparrar skyddet eller gar detsamma okansligt. Vid denna losning bortfalla hjalpkontakterna pa brytarna. Den Or verksam Oven nar transformatorn sattes under spanning utifran men kraver en sarskikl spanningstransformator maim transformatorbrytarna. Samma nackdel har Oven en annan fareslagen losning med magnetisk avbild, vilken inkopplas i och med att transformatorn sattes under spanning och upphaver inkopplingens verkan p0 relaet medelst en lika stor i motsatt riktning flytande inkopplingsstrain. According to other known methods, an occurring DC component or harmonics are used in the connection current to block the protection with the aid of electrical auxiliary and filter circuits. Furthermore, a solution has been compromised, comprising a voltage transformer connected between the transformer and its circuit breaker, according to which this voltage transformer is connected to a zero voltage relay, which at its attraction for a certain time sparingly protects or does the same indefinitely. With this release, the auxiliary contacts on the switches disappear. The Or operative Oven when the transformer was put under voltage from the outside but requires a special voltage transformer maim the transformer switches. The same disadvantage is that Oven has another dangerous solution with a magnetic image, which is switched on when the transformer is put under voltage and cancels the connection on the relay by means of an equally large switching current flowing in the opposite direction.

Vid den nedan beskrivna nya losningen av problemet elimineras joke blott de namnda nackdelarna hos de kanda ,anorclningarna utan darjamte ernas den anskade verkan med ett minimum av model. In the new solution to the problem described below, the joke only eliminates the mentioned disadvantages of the kanda, the anorculations without darjamte ernas the desired effect with a minimum of model.

Anordningen beror pa den omstandigheten, att inkopplingsstrommen i differentialrelaet alstrar ett vridmoment med frAn natfrekvensen avvikande frekvens. Enligt uppfinningen forses nu relaet med ett svangbart organ, vilket Or sa avstamt, att det rakar i svangningar under inverkan av overtoner i inkopplingsstriimmen och darigenom hindrar differentialrelaet Iran att arbeta, men att det daremot joke forsattes i svangningar av differensstrOmmar av natfrekvens, och att vidare genom det svangbara organet ett tidrela i differentialrelaets utlosningskrets styres, vilket tidrela slar till med fordrOjning men slar ifran utan fordroj ning. The device is due to the fact that the switching current in the differential relay generates a torque with a frequency deviating from the night frequency. According to the invention, the relay is now provided with a pivotable member, which Or said descended from, that it shaves in oscillations under the influence of harmonics in the connection strip and thereby prevents the differential relay Iran from working, but that the joke was continued in fluctuations of differential currents through the pivoting member a time relay in the differential circuit of the differential relay is controlled, which time relay switches on with delay but switches off without delay.

I fig. 1 pi ritningen Oro visade nagra strainvagor i belastningsstrommen i far en transformator, varvid vagorna antagits vara sinusformade. En av denna strain magnetiserad elektromagnet utovar en met kvadraten pa strommen proportionell kr aft, vilken Or askadliggj and med den. streekade kurvan k. Inkopplingsstrammen io far en transformator Or daremot ganska osymmetrisk, sasom visas i fig. 2, och dess kvadrat kommer att innehalla en 8verlagrad vagstrom av enkel natfrekvens. Kraften ko hos en harmed matad elektromagnet Or dad& omvaxlande star och liten, ja, Mrhallandet an rentav sOdant, att i praktiken de mindre kraftstatarna kunna Mrsummas gentemot de stora. Medan alltsa kraftstotarna vid normalstram intraffa med den dubbla natfrekvensen, hava de vid inkopplingen den enkla frekvensen. In Fig. 1 of the drawing Oro, some strain waves in the load current in a transformer are shown, the waves being assumed to be sinusoidal. An electromagnet magnetized by this strain exerts a square force on the current proportional to the current which is present with it. dashed curve k. The connection current io far a transformer Or, on the other hand, rather asymmetrical, as shown in Fig. 2, and its square will contain an 8-storey vaginal current of simple night frequency. The power of a harmed power electromagnet Or dad & alternating star and small, yes, Mrhallandet and even so, that in practice the smaller power states can be summed up against the big ones. Thus, during normal tightening, the power shocks occur with the double night frequency, they have the single frequency when connected.

Donna omstandighet nyttiggores enligt uppfinningen exempelvis medelst en anordning av I fig. 3 schematiskt visat slag. This condition is utilized according to the invention, for example by means of a device of the type schematically shown in Fig. 3.

Differentialrelaet har en av differensstrommen mellan transformatorns primar- och sekundarledningar magnetiserad relaspole b, vilken medelst ett ieke visat ankare utavar 2— — ett vridmoment pa axeln a. Detta yridmoment varierar vid differensstrom enligt kur- van K i fig. 1, -vid inkopplingsstrom enligt kurvan kc, i fig. 2. Pa en kring axeln a vridbar arm som barare sitter en kontakt c, som samverkar med en motkontakt d och tillsam- mans med denna styr stromkretsen for magnetisering ay spolen e hos utlOsningsrelfiet, vilket ar forsett med ett tidverk och sluter kontakten g i stromkretsen h for de icke visade utlosningsmag,neterna hos brytarna pa &Ilse sidor am transformatorn. Kontakten d är fast pa en bladfjader f, vilken tjanar sasom svangbart organ och yars egensvangningstal ãr aystamt till en frekvens, som fir lika med halva antalet av de kraftstotar, som framkallas av differensstrOmmen av natfrekvens. The differential relay has a relay coil b magnetized by one of the differential currents between the primary and secondary lines of the transformer, which by means of an armature (not shown) has a torque on the shaft a. the curve kc, in Fig. 2. On a shaft rotatable about the axis is a contact c, which cooperates with a counter-contact d and together with this controls the circuit for excitation at the coil e of the release relay, which is provided with a timer. and closes the contact in the circuit h for the tripping means (not shown), the networks of the switches on the sides of the transformer. The contact d is fixed on a leaf spring f, which serves as a pivotable member and its natural oscillation number is equal to a frequency equal to half the number of the force beats produced by the differential current of the night frequency.

Nar relict slar till, syanges kontakten c mot kontakten d, och strOmkretsen for spolen e hos utlosningsrelaet kan slutas. Magnetiseras nu relaspolen b med differensstrom av natfrekvens enligt fig. 1, sit yrider sig axeln a och darmed kontakten c mot bladfjadern f med kontakten d under inverkan ay kraftstotar, som folja pa varandra med den dubbla natfrekvensen. Sam tjadern fir aystamd till den enkla nfitfrekyensen, rakar den icke i svangningar, och kontakterna c, d forbliva slutna under tryck, sã att sá snort tidverket lop[ ut relaet sluter kontakten g. When the relic turns on, the contact c is sewn to the contact d, and the circuit for the coil e of the tripping relay can be closed. If the relay coil b is now magnetized with a differential current of the night frequency according to Fig. 1, the shaft a and thus the contact c move towards the leaf spring f with the contact d under the action of power beats, which follow one another with the double night frequency. Sam tjadern fir aystamd to the simple nfit frequency, it does not shave in oscillations, and the contacts c, d remain closed under pressure, so that so snort the time lop [out the relay closes the contact g.

Om darernot spolen e magnetiseras av inkopplingsstrommen, 'liken innehaller over-toner, sO motsvarar den kraft, med 'liken axeln a syanges, blott den enkla natfrekvensen enligt fig. 2, d. v. s. antalet av kraftst5- tarna per tidsenhet fir endast halften sà stort som vid differensstrom av natfrekvens. Da i detta fall den frekvens, yarmed kontakten c forsattes i rorelse, motsvarar egenfrekvensen hos fjadern f, sa svanger bade kontakten c och kontakten d. Mellan kontakterna c och d kan Tartar ingen yaraktig kontaktslutning uppsta, utan matningsstrommen for spolen e pa utlosningsrelfiet brytes upprepade ganger, sa att dess magnetiseringsvaraktighet joke racker till for att bringa relaet att sla till. If, on the other hand, the coil e is magnetized by the switching current, the body contains harmonics, then it corresponds to the force, with the same axis as the syanges, only the simple night frequency according to Fig. 2, i.e. the number of power units per unit time at differential current of night frequency. Since in this case the frequency at which the contact c was kept in motion corresponds to the natural frequency of the spring f, both the contact c and the contact d fluctuate. Between the contacts c and d, Tartar can not have an annual contact closure, but the supply current for the coil e on the release relay times, said that its magnetization duration joke racks to bring the relay to strike.

Enligt uppfinningen har salunda hela stabiliseringen av differentialrelaet under inkopplingen ernatts genom viss dimensionering ay fjadern i relaet; den arbetar riktigt, tillfarlitligt och automatiskt Yid alla farekommande driftsfall. According to the invention, the whole stabilization of the differential relay during the connection has been achieved by a certain dimensioning of the spring in the relay; it works properly, reliably and automatically Yid all dangerous operational cases.

Kontakten d skulle aven kunna yara fast anordnad, medan kontakten c är fast pa den avstamda fjadern, som dá konstruktivt fOrcues med relaets ankare. I stallet for att anvanda sjalva relaspolen och relakontakten kan man aven utfOra en sarskild apparat, t. ex. ett mellanrela, rued den mekaniska resonansfjadern, vilken blockerar differentialretact yid inkopplingsstrom och frigiyer detsamma vid symmetrisk strOmkurya. I stallet for att bringa fjadern i resonans medelst osymmetrivagen av kraften av natfrekyens, kan man aven utnyttja en annan blott i inkopplingsstrommen upptradande Overton for blockering ay relaet eller ocksa anvanda flera pa olika frekvenser avstamda anordningar. Fjadern behover lake utgoras av en bladfj ad er. The contact d could also be fixedly arranged, while the contact c is fixed on the descended spring, which is then constructively fastened with the armature of the relay. Instead of using the relay coil and the relay contact itself, a special device can also be designed, e.g. an intermediate relay, rued the mechanical resonant spring, which blocks differential retact yid coupling current and releases the same at symmetric current current. Instead of resonating the spring by the asymmetric wave of the force of the night frequency, one can also use another Overton appearing only in the connection current for blocking the relay or also use several devices tuned to different frequencies. The spring needs lake formed by a leaf spring.

Det är ocksâ likgiltigt, ay vilket slag differentialrelfiet resp. det anvanda mellanrelaet fir, ,om det dr forsett med drag- eller vridmagnet och om .det utgores av ett motorrela eller ay ett Ferrarisrela. It is also indifferent, ay what kind of differential relief resp. the intermediate relay used fir,, if it is equipped with a traction or rotating magnet and if it consists of a motor relay or a Ferrari relay.

Aystamning ay fjfidern f gores lampligert icke skarp, sit att fjadern kommer all svanga med Oven Yid vissa driftsmassigt forekommande ayikelser fran den enkla natfrekyensen. Denna bredd hos frekvensbandet for fjaderavstamningen kan installas resp. goras installbar medelst konstlade medel, t. ex. genom dampning. Aystamning ay fjfidern f gores lampligert ikke skarp, sit att fjadern kom all svanga med Oven Yid certain operationally occurring ayikelser fra den simple natfrekyensen. This width of the frequency band for the spring pedigree can be installed resp. made installable by artificial means, e.g. by steaming.

Claims

Patentanspralo

1. Device for preventing undesired switching on of differential relays when switching on inductive current consumers, which the relays protect, characterized in that the relay is a singable member, which Or said aystamt, that it continued in oscillations of harmonics in the switching current and thereby the differential relay prevents Iran from working but on the other hand was not continued in sewing by differential current of night frequency, and that further through the pivoting means a time relay in the differential relay trigger circuit is controlled, which time relay. strikes with delay but strikes without delay.

2. Device according to claim 1, characterized in that the pivotable member Or is tuned to a frequency which corresponds to half the number of the power beams generated by the differential current of night frequency.

Device according to claim 1, characterized in that the pedigree of the pivotable member is blurred, so that the member oscillates with a certain frequency range.

Device according to claim 3, characterized in that the frequency range can be determined by means of an installable steaming device.

Device according to claim 1, characterized in that the pivotable member is constituted by a spring derived from an Overton.

6. A device according to claim 5, characterized in that the spring carried one of the contacts Yid an electric relO.

7. Device according to claim 5, characterized in that a special intermediate relay Or, arranged to spar the action of the differential relay.

Device according to patent claim 5, characterized in that the relfiet with the aystamda. the contact spring consists of the differential relay itself. Stockholm 1948. Kungl. Boktr. P. A. Norstedt & SUner 480089 Till Pitentet N: o 123 7 F7 f7g.2 h. GENERALSTABENS LITOGR. INSTITUTION