SE123715C1

SE123715C1 -

Info

Publication number: SE123715C1
Authority: SE
Publication date: 1948-01-01

Description

Uppfinnare: J. Jonas och 0. Lardelli. Inventors: J. Jonas and 0. Lardelli.

Prioritet begdrd frdn, den 11 april 1942 (Se7tivei2). Priority requested from April 11, 1942 (Se7tivei2).

I manga fall aro danapspolar med dubbelkrokt karakteristik lanaptiga, enar deras magnetiseringskurya har en rak del, -vilkens forlangning ej gar genom origo i det koordinationssystem dar ordinatan betecknar flodet och abscissan MMK. Den forsta krOkningen resp. det forsta knaet pi magnetiseringskurvan befinner sig i narheten av origo i koordnatsystemet och erhalles pa foljande satt. Damspolens magnetkrets fir avbruten av ett luftgap. Detta luftgap ar einellertid korislutet av en for det mesta av nagra fâ jarnplatar bestaiende brygga riled litet tvarsnitt varfor magnetkrelsen vid laga varden pa MMK verkar som hell sluten. \rid storre varden pa MMK daremot blir jarnbryggan mycket snart mat-tad, under det att den Ovriga delen av magnetkretsens jarnkarna iinnu Or helt omattad. Om till Raj d av mattningen bryggans permeabilitet narmar sig noll, blir detta praktiskt taget liktydigt med uppkornsten av ett luftgap, motsvarande det ursprungliga. Den pa detta forsta mattningskna foljande delen av karakteristikan forloper ratlinigt, tills det andra knaet uppnas genom mattningen i jarnet i beta magnetkretsen. Om man ritar upp spanningskurvan for en sadan dampspole som -funktion av magnetiseringsstrommen, yisar denna nara nog samma karakteristiska fOrlopp som magnetiseringskurvan. Aven denna ar forsedd med en krokt del i narheten av koordinatssystemets origo, en mellanliggande rak del och en darpa foljande andra krokt del. In many cases, danap coils with double-hook characteristics are lanaptiga, one their magnetization curia has a straight part, -which demand does not go through the origin in the coordination system where the ordinate denotes the river and the abscissa MMK. The first curvature resp. the first node of the excitation curve is located near the origin in the coordinate network system and is obtained as follows. The female coil's magnetic circuit is interrupted by an air gap. However, this air gap is closed at the end of a bridge with a mostly small cross section consisting of a few iron plates, which is why the magnetic circuit at the low value of the MMK seems to be completely closed. On the larger side of the MMK, on the other hand, the iron bridge is very soon fed up, while the other part of the iron circuits of the magnetic circuit inside Or is completely unsaturated. If to Raj d of the matting the bridge's permeability approaches zero, this becomes practically synonymous with the grain of an air gap, corresponding to the original. The following part of the characteristic on this first mating axis proceeds linearly, until the second knot is reached by the mating in the iron in the beta magnetic circuit. If one draws the voltage curve for such a vapor coil as a function of the excitation current, it has almost the same characteristic course as the excitation curve. This is also provided with a crooked part near the origin of the coordinate system, an intermediate straight part and a narrow second crooked part.

Dessutom är det kant att luftgapet i dampspolens magnetkrets atminstone delvis kort- slutes av en brygga med litet tvarsnitt, vilken utgores av en jfirnlegering, som blir starkt mattad redan vid mycket liten MMK. Detta steg astadkommer vid lag magnetisering ett skarpt mattningskna. mom tekniken finnas viktiga anvandnings-omraden for en kombination av dampspole med kondensator. Salunda Or det exempelvis kant att anvanda en kombination, bestaende av en dampspole och en med denna parallellkopplad kapacitet som skydd mot overslag till stativet hos en generator, i del att kombinationen i fraga inkopplas mellan generatorlindningens nollpunkt och j ord. Den felstr5m (jordslutningsstrom), som i handelse av starning flyter igenom kombinationen, tjanar darvid till magnetisering av ett skyddsrela. Detta skall trada i funktion med sanama kanslighet, oberoende av om tiverledning finnes mellan stativet och en lindningsdel, som befinner sig narheten av generatorklamman, som for full fasspanning, eller i narheten av lindningens nollpunkt. Samma kanslighet kan man emellertid endast uppna., om den stain], som bringar relaet att trada i funktion, sà mycket som mojligt kan hallas konstant mom det On-shade skyddsomradet, saledes oberoende av den spanning, corn alstrar strommen. For att uppna delta har man hittills inkopplat av spanningen beroende motstand i jordningskretsen, vilka emellertid endast mom ett -visst spanningsomrade uppfylla det stallda anspraket. Varje utvidgning av detta omrade ãr Onskvard och betyder ett tekniskt framsteg. Anya.nder man nu en dampspole med en med densamma parallellkopplad kapacitet, vars spanningskarakteristika loper nara nog parallellt med den raka delen av dampspolens spanningskarakteristika, sa erhalles ett fOrstorat spanningsomrade for en konstant strOm. Annu fordelaktigare Or det, att corn skydd mot genomslag till stativet yid en generator anyanda en anordning, dar demur dampspole ligger i serie med kapaciteten. En sadan kombination uppvisar Mom det omrade, dar de hada spanningskurvorna forlopa parallellt, en konstant spanningsdifferans mellan andarna pa serien, sfi. att skyddsrelaet i detta fall oberoende av felstrommens storlek far konstant spanning. Aven i detta fall nas skyddsomradet genom 2— — det att man i dampspolens luftspalt insatter ett overbryggningsstag av jam, som mattas fort. In addition, the air gap in the magnetic coil's magnetic circuit is at least partially short-circuited by a bridge with a small cross-section, which is formed by an iron alloy, which becomes strongly matted even at very small MMK. This step achieves a sharp matting knee during low magnetization. Mom technology is important areas of application for a combination of steam coil with capacitor. Salunda Is it, for example, possible to use a combination, consisting of a steam coil and one with this parallel connected capacity as protection against overturning to the stand of a generator, in part that the combination in question is connected between the zero winding of the generator winding and ground. The fault current (earth fault current), which flows through the combination in the act of solidification, thereby serves to magnetize a protective relay. This shall operate in the same probability, regardless of whether there is a conductor wire between the frame and a winding part, which is close to the generator clamp, as for full phase voltage, or close to the zero point of the winding. The same probability can only be achieved, however, if the stain] which causes the relay to operate, as much as possible, can be kept constant within the On-shade protection area, thus independent of the voltage generated by the current. In order to achieve delta, the voltage-dependent resistor in the earthing circuit has hitherto been connected, which, however, only in a certain voltage range fulfill the set claim. Every extension of this area is Onskvard and means a technological advance. If you now create a steam coil with a capacitance connected to it in parallel, the voltage characteristics of which run almost parallel to the straight part of the voltage characteristics of the steam coil, then an enlarged voltage range is obtained for a constant current. Even more advantageous is the fact that the corn protection against breakthrough to the stand yid a generator anyanda a device where the steam coil is in series with the capacity. Such a combination shows Mom the area, where the two voltage curves run parallel, a constant voltage difference between the spirits in the series, sfi. that the protective relay in this case, regardless of the size of the fault current, receives a constant voltage. Even in this case, the protection area is obtained by inserting a bridging rod of jam into the air gap of the steam coil, which mats quickly.

Foremal for uppfinningen ar salunda en anordning vid en generator for skydd mot Over-slag till stativet med anvandning av en melIan generatorlindningens nollpunkt och jord inkopplad impedans, som bestar av en mattad dampspole och en kondensator och till -Olken ett rela ar anslutet, som i handelse av storning sattes i funktion, varvid enligt uppfinningen impedansen bestar av en dampspole med en med denna i serie kopplad kapacitet, vars spanningskurva forloper atminstone Mina"- melsevis parallellt med den raka delen av dampspolens spanningskurva, sO. att relict matas med en Over ett vidstrackt spanningsomrade konstant spanning. The object of the invention is thus a device in a generator for protection against overheating to the stand using an impedance connected between the zero winding of the generator winding and ground, which consists of a matte steam coil and a capacitor and to -Olken a relay is connected, as in act of interference was put into operation, whereby according to the invention the impedance consists of a steam coil with a capacitance connected thereto in series, whose voltage curve extends at least Mina "- substantially parallel to the straight part of the steam coil voltage curve, so that relict is fed with an Over one wide voltage range constant voltage.

Uppfinningen beskrives i det foljande med ledning av bifogade ritning: I fig. 1 ar dampspolen 1 seriekopplad med en kapacitet k, vars spanningskarakteristik skall ha samma forlopp, som den rata linjen h i fig. 2. Den senare loper parallellt med den rata linjen f av dampspolens karakteristik. Kombinationen av dampspolen och kapaciteten ar jordad mellan generatorns q nollpunkt 0 och jord. Dessutom ar i jordningskretsen i serie med kombinationen kopplad en impedans in, som ar sa dimensionerad, att den begransar den vid kombinationen rnaximalt upptradande strommen till onskat maximalvarde. Till trefasnatet n ar aven en summa-stramtransformator S ansluten. The invention is described in the following with reference to the accompanying drawing: In Fig. 1 the steam coil 1 is connected in series with a capacitance k, the voltage characteristic of which must have the same course as the straight line in Fig. 2. The latter runs parallel to the straight line f of steam coil characteristics. The combination of the steam coil and the capacity is grounded between the generator's zero point 0 and ground. In addition, an impedance is connected in the earthing circuit in series with the combination, which is so dimensioned that it limits the current occurring at the combination to the maximum maximum value to the desired maximum value. A sum current transformer S is also connected to the three-phase circuit.

Sasom fig. 2 visar, ar skyddsomradet givet av skillnaden mellan strOmmarnavar- vid i2 betecknar den maximalt verkande felstrOmmen, jordningsstrommen, under det att ar den felstrom vid vilken dampspolens forsta matningskna uppnas. mom dessa granser ar skillnaden mellan spanningarna v och konstant. Ju brantare mattningen stiger i bryggan, desto mindre ar iz och desto narmare ligger den skyddade anden av van j e faslindning hos generatorn till dess nollpunkt. Om aven denna shall skyddas, sa kan densamma pa kant salt forskjutas utat medelst osymmetriskt anslutna impedanser frau lindningens nollpunkt d .v. s. forlaggas i spanningstriangeln. I praktiken kommer denim algard langre att erfordras vid anordningen enar skyddet stracker sig Over hela lindningen till helt nara nollpunkten. As Fig. 2 shows, the protection range is given by the difference between the currents at which i2 denotes the maximum acting fault current, the earthing current, while being the fault current at which the first supply coil of the steam coil is reached. Although these limits are the difference between the voltages v and constant. The steeper the mating rises in the bridge, the smaller the ice and the closer the protected spirit of normal phase winding of the generator is to its zero point. If this is also to be protected, then the same edge salt can be displaced outwards by means of asymmetrically connected impedances from the zero point of the winding, i.e. s. relocated in the voltage triangle. In practice, denim algard longer will be required at the device enar protection extends Across the entire winding to near zero.

Det ar lampligt att valja impedansen m sa, att felstrommen ej uppnar ett varde som kan fororsaka jarnbrand. It is appropriate to select the impedance so that the fault current does not reach a value that can cause iron fire.

Yid en anordning av det liar behandlade slaget medfor uppfinningen pa grund av seriekopplingen mellan dampspole och kapacitet den stora fordelen gentemot parallellkopplingen, att sasom foljd av den Mom ett vidstrackt omrade konstanta spanningen skyddsrelaet tillf Ores en av felstrommens storlek oberoende spanning, d. v. s. reldets magnetiseringsstrom ar endast i ringa omfattning variabel. Due to the series connection between the steam coil and the capacity of the device of the type treated, the invention has the great advantage over the parallel connection that slightly variable.

Claims

1. Patent claim: Device for a generator for protection against overturning to the stand using an impedance connected between the zero winding of the generator winding and ground, which consists of a matte steam coil and a capacitor and to which a relay Ar is connected, which was inserted in function, characterized in that the impedance consists of a steam coil with a double-hook characteristic and a capacitance connected thereto in series, the voltage curve (h) of which runs at least approximately parallel to the straight part. (f) by the voltage curve of the steam coil, so that the relay is supplied with an over a wide range of constant voltage. Stockholm 1948. Kungl. Boktr. P. A. Norstedt & Slner 480089.