ISOLATION TRANSFORMER. FOR 3 rd HARMONIC FILTERING TSA INSTRUCTIONS MANUAL M A

Transcription

1 ISOLATION TRANSFORMER FOR 3 rd HARMONIC FILTERING TSA INSTRUCTIONS MANUAL M-983-0A

2 INTRODUCTION There is a lot of electrical supply istallatios where most of the loads are sigle phase, supplyig a rectifier plus a filter. This case is very commo i office buildigs, big stores, TV studies, where there is a lot of computers ad electroic devices usig DC supply. I such istallatios there is a particular type of problem with harmoics of 3 rd order ad their multiples (called some times the triples ). The curret of the triples add o the eutral i phase, istead of addig like vectors at 0º. Because of that, the curret at the eutral may be higher tha the curret at the phase cables, eve i case that the three phases are perfectly balaced. This causes uexpected trippig of thermal protectios ad overheatig of the eutral cables. The TSA filters are the optimal solutio to solve such problems, sice the filterig of third harmoic by other types of passive filters may cause the saturatio of trasformers ad may spoil the situatio istead of improvig. The basis of the TSA is a three phase D-Y isolatig trasformer, which elimiates the third harmoic upstream. At the output there is also a wide bad passive filter to damp dow the 5 th ad 7 th harmoics. LOCATION AND SIZE OF THE TSA FILTERS.. Where to locate the TSA? It is importat to locate the TSA as close as possible to the disturbig loads. Because of that we do t recommed the solutio of big cetralized TSA filters to compesate the whole power distributio. It s better to split up the filter i several smaller filters, placed as close as possible of the sigle phase lies causig the disturbaces. I that way the currets upstream the TSA will be practically exempt of 3 rd harmoic.. How to size the TSA? The TSA filters are selected by its total power i kva, but to calculate the curret that they ca deliver, a power factor correctio must be applied. Such power factor depeds o the distortio of the curret that the TSA must supply dowstream to the loads. To calculate the kva of the TSA, the fudametal ad the most sigificat harmoics to be supplied to the load side must be kow ad the the rated power may be calculated accordig to the followig formula. I SVA ( ) = 73, * UC * I * ( * % ) 00 Where : U C is the phase to phase voltage at the secodary side (usually 0V or 30V) I is the fudametal curret at the load side. is the harmoic order %I is the % of harmoic (Icludig the 3 rd harmoic to be filtered) The coefficiet FS = ( * % ) 00 I is amed the overload factor REMARK: The curret writte i the characteristics plate is the rated curret give by the weighted additio of fudametal ad all the harmoics as follows: I * ( * % ) 00 I

3 3 TSA FILTER DESCRIPTION. (See schematics). The TSA filter is formed by the followig parts : ISOLATION TRANSFORMER: With the followig characteristics. Primary side: Delta coectio. Iput termials: U, V, W, N, PE (see wire diagram) Secodary side: Star coectio, usually with 30 V phase to phase. The eutral coductor is ot used i the load. The star poit is coected to the protectio earth cable (PE). Output termials: U, V, W., PE (see wire diagram) LC FILTER: 5 th harmoic filter THREE PHASE POWER CIRCUIT BREAKER: The size depeds o the rated power of the TSA. The circuit breaker is placed at the primary side. The breaker trips i case that a earth leakage is detected at the secodary side circuit. SINGLE PHASE AUXILIARY SUPPLY CIRCUIT BREAKER: This breaker protects the earth leakage relay ad other auxiliary protectio circuits. EARTH LEAKAGE RELAY: This relay provides a protectio i case of earth leakage at the load side. The stadard protectio relay is adjustable from 30mA to 300mA ad has a adjustable delay. 4 TECHNICAL CHARACTERISTICS TSA filters are ofte desiged uder particular specificatios, but all of them have a set of commo characteristics which are listed below. Trasformer Stadard primary voltage V phase to phase Stadard secodary voltage V phase to phase Short circuit voltage ratio ucc%... 6% Power kva... Depedig o type Costructive stadards... EN LC Filter Resoace frequecy... 5 Hz 4. Types ad compoets (see wire diagram) TYPE TR (kva) L Three phase C RD IA (A) IA (A) TSA-0 0 R CV-40-0 WRTR-35/03 0 TSA-0 0 R CV-40-0 WRTR-35/03 40 TSA R CV-40-0 WRTR-35/03 63 TSA RB CV-40-0 WRTR-35/03 80 TSA RB CV-40-0 WRTR-35/03 00 TSA RB CV-40-0 WRTR-35/03 60 TSA RB CV-40-0 WRTR-35/03 50

4 4. Dimesios: TYPE A B H TSA-0 TSA-5 TSA-0 TSA-30 TSA-40 TSA-50 TSA-80 TSA-00 5 INSTALLATION AND SET-UP. 5. Importat remarks! Loads at the secodary side must be coected at the SALIDA / OUTPUT side phase to phase. (U-V, V-W, W-U, see wire diagram) To get the maximum effectiveess of the TSA filter the loads must be as balaced as possible betwee the three possible pairs of phases (U-V, V-W, W-U, see wire diagram) Never coect a load betwee a phase ad the PE (protectio earth) cable. Loads which do ot produce 3 rd harmoic, as icadescet lightig, heatig, etc., do ot eed to be coected to the TSA output. They ca be coected at the primary side betwee phase ad eutral The TSA must be coected to mais by the side amed ENTRADA/INPUT. The three phases shall be coected to U, V, Wad the eutral to N. The eutral is used oly as auxiliary supply for the protectio elemets. Do ot coect it to the load side. (see fig.) Coect the PE termial of the TSA to the protectio earth cable i the existig istallatio. Loads to be filtered must be coected to the side amed SALIDA/OUTPUT. Termials U, V, W without the eutral (see wire diagram) The 30 V output is phase to phase. All the sigle phase loads must be coected phase to phase. If the TSA is mouted i a existig istallatio where loads were supplied betwee phase ad eutral, a ew distributio has to be made, tryig to keep the maximum balace betwee the pairs of phases (U-V, V-W, W-U), see wire diagram. The earth cable to be distributed to the load is the already existig earth, coected to PE Adjust the sesitivity ad the desired delay for the earth leakage relay accordig to the load eeds ad the desired selectivity. For TSA uits with rated power below 50 kva, adjust i the

5 low rage (30 to 00mA) For higher powers the threshold ca be icreased up to 300mA. I case that the relay trips, check the leakage curret. REMARK! : I case that the loads are maily sigle phase supplyig computers, priters, speed cotrollers, etc., the trip threshold of leakage relay must be icreased due to the EMI filters leakage. 6 TROUBLE SHOOTING AND MAINTENENCE. Check periodically that the earth leakage relay operates properly. Use the test push butto of the relay. Check periodically that the rated power of the TSA is ot surpassed because of the additio of ew loads. (Take ito accout the overload factor due to harmoics) If ew loads have to be added, take care of the load balace. Split the loads up i the three lie pairs (U-V, V-W, W-U), see wire diagram. 7 SCHEMATICS