SURGE DURABILITY AND IMPROVED TRANSFORMER PROTECTION

Transcription

1 Fusing Equipment Tandem ELF Current-Limiting Dropout Fuse Electrical pparatus GENERL The Cooper Power Systems Tandem ELF current-limiting fuse is designed for transformer protection. The Tandem ELF fuse can be applied for fusing single-phase transformers and for fusing three-phase transformers (or three-phase banks of single-phase transformers). This fuse combines the features of a series fuse link and a backup current-limiting fuse in one convenient package. The Tandem ELF fuse (refer to Figure 1) includes a unique design for fast replacement of the backup current-limiting fuse after a high fault current operation. The fuse link holder is accessible for replacement of the fuse link after a low fault current operation or excessive transformer overload current. The fuse link holder of the Tandem ELF is specifically designed to accommodate standard Cooper Power Systems Type D (D-Link) and Kearney Type X (X-Link) high surge current fuse links. These fuse links make it possible to protect the transformer from damage due to overload, and at the same time gain increased surge current withstand capability over conventional fuse links to help eliminate nuisance fuse blowings. The Tandem ELF fuse uses the Cooper Power Systems Companion II (25K rated) backup current-limiting fuse (reference for more detailed information) to interrupt high magnitude fault currents. The backup currentlimiting fuse also limits the amount of energy let-through to the transformer, which prevents the possibility of a catastrophic tank rupture. TRNSFORMER OVERLOD PROTECTION The Tandem ELF fuse offers the ability to protect the transformer from damaging overload currents. The availability of a wide range of ampere rated Type D and Type X fuse links allows for the selection of a fuse link that has a melting characteristic that closely matches the NSI safe loading curve for the respective transformer. This allows for proper transformer protection, even for smaller kv rated transformers. Figure 1. Tandem ELF Current-Limiting Dropout Fuse (left: Tandem ELF in Type L cutout). SURGE DURILITY ND IMPROVED TRNSFORMER PROTECTION The Tandem ELF fuse is a surge durable transformer fuse particularly well suited for applications in high isokeraunic areas where there is a high probability of lightning surges. When it is used with the Surge Durable Cooper Power Systems D-Link or Kearney X-Link, the unit can withstand high surge currents that might be discharged through a surge arrester. Therefore, the surge arrester can be connected on the load side of the fuse and closer to the transformer. This shortens the lead length to the arrester and provides the best overvoltage protection. In this configuration, the Tandem ELF fuse is actually protecting the arrester as well as the transformer. This would not be possible with similar ampere ratings of conventional type links because of the high probability of damage due to the lightning surge current passing through the link. The benefits of high surge current withstand capability of the D-Link and X-Link are achieved without sacrificing the ability of the fuse links to provide overload protection for the transformer. ENHNCED POWER QULITY ND IMPROVED SERVICE CONTINUITY The Tandem ELF current-limiting fuse will enhance power quality of the system and improve the service continuity during high magnitude faults due to operation of the backup current-limiting fuse. The duration of the voltage dip associated with system short circuits will be limited to the short melt time of the current-limiting section of the Tandem ELF fuse. Immediately after melting, the arc voltage generated by the current-limiting fuse will support system voltage until the fault is interrupted by the fuse. For high fault currents, the duration of the voltage dip associated with the melt time of the current-limiting fuse will be well within the allowable limits for sensitive electronic equipment as defined by CEM curves. MINIMIZES EQUIPMENT DMGE The Tandem ELF s backup currentlimiting fuse will interrupt high magnitude fault currents while also limiting the amount of current and energy let-through to the transformer. The backup current-limiting fuse will limit the let-through current to minimize the October 1998 New Issue Printed in U.S.. 1

2 Tandem ELF Current-Limiting Dropout Fuse SILVER-PLTED UPPER CONTCT C UPPER PULL RING CONNECTOR llows for the use of a loadbreak tool to open and hookstick to close the fuse into the upper contact of an interchangeable cutout. PULL RING HIGH PURITY SILIC SND FILLER Specific particle size, purity and compaction gives the heat-absorbing and arc-quenching properties necessary for consistent clearing and low energy let-through levels. URETHNE COTED FIERGLSS REINFORCED EPOXY HOUSING Provides strength and maintains integrity of the fuse during any interruption. FUSE CP MIC SPIDER Provides stable winding support without generating gas and pressure buildup during fuse operation. HIGH-CURRENT CLERING SECTION The pure silver element remains stable under current cycling and thermal stress, providing consistent melt characteristics. The element effectively controls and limits both current and energy (I 2 t) let-through levels during interruption. CKUP CURRENT-LIMITING FUSE NMEPLTE Includes easy-to-read fuse voltage, current, interrupting ratings and catalog number. CKUP CURRENT-LIMITING FUSE The 25K Companion II fuse provides energy-limiting capability during a high magnitude fault operation up to 50 k. LIFTING EYE llows for the use of a hookstick to install the Tandem ELF fuse into the lower contact of an interchangeable cutout. FUSE LINK HOLDER llows the standard NSI/IEEE fuse links to be installed for operation during a low magnitude fault or overload current. TNDEM ELF FUSE NMEPLTE Includes easy-to-read fuse voltage ratings. It also includes the voltage rating of the compatible interchangeable cutout mounting. FUSE LINK Specifically designed to use the high surge current Type D and Type X fuse links to protect the transformer from overloads and provide increased surge current withstand capability. Figure 2. Line illustration of Tandem ELF fuse with dimensions. (Refer to Table 2.) 2

3 TLE 1 Tandem ELF Fuse - Electrical Characteristics Voltage Three-Phase Single-Phase Minimum Maximum Maximum Class Voltage Rating Voltage Rating Melt I 2 t Clear I 2 t Interrupting Current (kv) (kv) (kv) (k 2 sec) (k 2 sec) (k rms Symmetrical) TLE 2 Tandem ELF Fuse Dimensional Data (Refer to Figure 2) in Inches (mm) Cutout Rating Tandem ELF Voltage/IL Rating Voltage Class (kv) (kv) C 15/95 & (328) (289) 7.47 (190) 27/125 & (417) (378) 7.47 (190) 27/125 & (417) (378) 7.47 (190) possibility of transformer tank rupture from high magnitude internal faults or to minimize damage to the tank or bushing that might result from bushing flashovers. INSTLLTION The Tandem ELF fuse is designed to be mounted in 15 kv rated 95 kv and 110 kv IL or 27 kv rated 125 kv and 150 kv IL interchangeable open distribution cutouts. The applicable interchangeable cutouts include Cooper Power Systems Type L, S&C Type XS,.. Chance Type C, and Type ICX. The Tandem ELF fuse is easily single hotstick installed due to its small size. Refer to Service Literature Section S for more information on the installation and refusing instructions. PRODUCTION TESTS Tests are conducted on 100% of production TNDEM ELF fuses in accordance with Cooper Power Systems requirements. Physical Inspection I 2 t Testing of Companion II ackup Current-limiting fuses Resistance Testing of Companion II ackup Current-limiting fuses Helium Mass Spectrometer Leak Testing of Companion II ackup Current-limiting fuses TLE 3 Tandem ELF Fuse Voltage pplication System Voltage (kv) Recommended Tandem ELF Voltage Class Rating (kv) Nominal Maximum Wye Delta / / / / / / / / / / / / / / / / * 13.2/ / * * 14.4/ / * * * For single phase applications on delta systems, one Tandem ELF fuse of this rating is required in each phase. PPLICTION Voltage Rating Selection The Tandem ELF fuse has voltage ratings compatible with most common distribution voltages. The most common distribution voltages for different transformer connections are shown in Table 3. For system voltages other than those listed, consult your Cooper Power Systems representative. Current Rating Selection The current rating for the Tandem ELF fuse is dependent on the selected fuse link. Table 4 shows the recommendations for the selection of the Type D and Type X fuse link in single-phase and three-phase applications. The backup current-limiting fuse of the Tandem ELF fuse has a fuse rating of 25K, which means it can be used in series with a maximum of a 25 Type K fuse link. The continuous current capacity of this backup current-limiting fuse is 50. 3

4 Tandem ELF Current-Limiting Dropout Fuse Delta-Connected Primary Wye-Connected Primary N N N C C FIGURE FIGURE FIGURE C FIGURE D FIGURE E FIGURE F Figure 3. Schematic of primary voltage system connections. TLE 4 Type D and Type X Fuse Link* Recommendations for Distribution Transformers in Single-Phase and Three-Phase pplications (Refer to Figure 3 for primary voltage connections) /4160Y /8320Y Transformer Figs. and Fig. C Figs. D, E and F Figs. and Fig. C Figs. D, E and F Size per phase Rated Link Rated Link Rated Link Rated Link Rated Link Rated Link (kv) mps Rating mps Rating mps Rating mps Rating mps Rating mps Rating /12470Y 7620/13200Y 7970/13800Y Transformer Figs. and Fig. C Figs. D, E and F Figs. D, E and F Figs. D, E and F Figs. and Fig. C Size per phase Rated Link Rated Link Rated Link Rated Link Rated Link Rated Link Rated Link (kv) mps Rating mps Rating mps Rating mps Rating mps Rating mps Rating mps Rating /20800Y /24940Y Transformer Figs. D, E and F Figs. and Fig. C Figs. and Fig. C Figs. D, E and F Size per phase Rated Link Rated Link Rated Link Rated Link Rated Link Rated Link (kv) mps Rating mps Rating mps Rating mps Rating mps Rating mps Rating NOTE: Table shows recommended fuse ratings based on the use of Cooper Power Systems Tandem ELF fuse time current characteristics defined in R , June Recommendations provide overload protection (fusing ratio) between 200% and 300% rated load. Fusing Ratio = Fuse Min. Melt 300 sec. x 100 Transformer Full Load Current *Kearney Type X fuse links for 1/3 through 2 ratings and Cooper Power Systems Type D fuse links for 3 through 20 ratings. 4

5 ORDERING INFORMTION Selecting a Catalog Number To select a catalog number, determine the Tandem ELF fuse voltage and current rating from the PPLICTION SECTION on page 3. For Tandem ELF fuse ordering (including fuse link), choose the base catalog number from Table 5 and complete the number by selecting the appropriate fuse link code from Table 6. Example: T425KD To select a 15 kv Class Tandem ELF fuse with a 5 fuse link for a 95 kv or 110 kv IL interchangeable cutout. TLE 5 Tandem ELF Fuse Catalog Numbers (Includes all parts shown in Figure 4) Tandem ELF fuse Catalog Number Cutout Rating Voltage/IL Rating Tandem ELF Voltage Class Voltage Rating (kv) Interrupting Rating ase Fuse Link Code Weight lbs (kg) (kv) (kv) Three-Phase Single-Phase (k Sym.) Catalog Number Digits 6 and 7 15/95 & T425 Refer to Table (1.62) 27/125 & T4C25 Refer to Table (1.65) 27/125 & T9C25 Refer to Table (2.35) Notes: To order a Tandem ELF fuse without a Type D or Type X fuse link, leave digits 6 and 7 blank and order the base catalog number in Table 5. TLE 6 Tandem ELF Fuse- Fuse Link Current Rating Selection Current Fuse Fuse Link Rating Link Catalog () Code Number ONLY.33 X X CX DX EX FX GX HD FL3D3 4 JD FL3D4 5 KD FL3D5 7 LD FL3D7 10 MD FL3D10 15 ND FL3D15 20 PD FL3D20 dd the fuse link code to the end of the base catalog number in Table 5. FUSE CP (included with fuse link holder) TYPE D OR TYPE X FUSE LINK HRDWRE (included in hardware kit) UPPER PULL RING CONNECTOR (included in hardware kit) CKUP CURRENT-LIMITING FUSE HRDWRE (included in hardware kit) FUSE LINK HOLDER Figure 4. Tandem ELF fuse parts. TLE 7 Tandem ELF Fuse Replacement Parts Only Cutout Rating Tandem ELF Voltage/IL Rating Voltage Class Fuse Link Holder ackup Current-Limiting Hardware Kit* (kv) (kv) Catalog Number Fuse Catalog Number Catalog Number 15/95 & T400 FH8KV25K THWKIT 27/125 & T4C00 FH8KV25K THWKIT 27/125 & T9C00 FH17KV25K THWKIT * Hardware kit includes one upper pull ring connector, two bolts and two lock washers for installing the backup current-limiting fuse. 5

6 Tandem ELF Current-Limiting Dropout Fuse New Installations lncludes Type L Cutout Mounting and Tandem ELF Fuse To order Tandem ELF fuse and mounting: (1) Select base catalog number in accordance with desired cutout and Tandem ELF Fuse ratings using Table 8. (2) Complete the number by selecting the appropriate fuse link code from Table 9, and add it to the end of the chosen catalog number in Table 8. Example: To select a 27 kv Class Tandem ELF in a 27 kv, 125 kv IL Type L cutout with a 20 fuse link, (1) Select base catalog number L9CTP15 from Table 8 and (2) Select the fuse link code P from Table 9. Therefore order catalog number L9CTP15P. TLE 8 Tandem ELF Fuse Catalog Numbers New Installations* Type L Cutout Tandem ELF Voltage Ratings (kv) Voltage/IL Voltage Class Interrupting Rating ase Fuse Link Rating (kv) (kv) Three-Phase Single-Phase (k Sym) Catalog Number** Code 15/ L4TP12 Refer to Table 9 15/ L4TP12 Refer to Table 9 27/ L9CTP L9CTP15 Refer to Table 9 27/ L9DTP L9DTP15 Refer to Table 9 Notes: * Refer to Catalog Section for more detailed information on the Type L interchangeable cutout. lncludes mounting, Tandem ELF fuse and fuse link (if appropriate fuse link code added to catalog number). ** Standard unit includes tin-plated bronze parallel-groove connector and NEM Type crossarm mounting bracket. Refer to Table 10 Type L Cutout Connector/racket Options for optional connectors and brackets. Refer to Table 9 for fuse link current rating selection and add the fuse link code (digit 9) to the end of the catalog number in Table 8. If no fuse link desired, add 0 in digit 9 of the base catalog number. TLE 9 Type L Cutout With Tandem ELF Fuse Fuse Link Current Ratings Selection Digit 9 Fuse Link Code NONE C D E F G H J K L M N P Notes: 0 in digit 9 defines no fuse link supplied with the Tandem ELF fuse. Type L Cutout Connectors/rackets CONNECTORS For new installations, the Tandem ELF fuse is mounted in a Type L open distribution cutout. The Type L cutout includes, as a standard, a tin plated bronze parallel-groove connector. The parallel groove connector fits a conductor range of #8 solid to 250 MCM. Tin plated bronze eyebolt and large eyebolt connectors are also available. The eyebolt connector fits a conductor range of #8 solid to 2/0 stranded and the large eyebolt connector fits a conductor range of #6 solid to 250 MCM. Refer to Table 10 for the different connector catalog code options. RCKETS The Type L cutout is shipped with a NEM Type mounting bracket as a standard. Refer to Table 10 for the mounting bracket catalog numbering codes. TLE 10 Type L Cutout Connector/racket Options Catalog Number* 5 th Digit 6 th Digit Type L Cutout Connector/racket Description P 0 Includes parallel groove connector; deletes crossarm mounting bracket P 1 Includes parallel groove connector and NEM Type crossarm mounting bracket P 3 Includes parallel groove connector and extended crossarm mounting bracket E 0 Includes eyebolt connector; deletes crossarm mounting bracket E 1 Includes eyebolt connector and NEM Type crossarm mounting bracket E 3 Includes eyebolt connector and extended crossarm mounting bracket L 0 Includes large eyebolt connector; deletes crossarm mounting bracket L 1 Includes large eyebolt connector and NEM Type crossarm mounting bracket L 3 Includes large eyebolt connector and extended crossarm mounting bracket *Refer to Catalog Number in Table 8. 6

7 DDITIONL INFORMTION Refer to the following reference literature for application recommendations: S Tandem ELF Fuse Installation Instruction R Tandem ELF Fuse Time Current Characteristic Curves Companion II ackup Current-Limiting Fuse Catalog Section R Recommended D-Link Primary Fusing for Distribution Transformers Type L Open Distribution Cutout Catalog Section 7

8 ISO 9001:2000-Certified Quality Management System 1998 Cooper Power Systems, Inc. ELF and Kearney are trademarks of Cooper Industries, Inc. Companion is a registered trademark of Cooper Industries, Inc. P.O. ox 1640 Waukesha, WI Printed on Recycled Paper MI 10/98