ECOVAR High Voltage Power Capacitors are manufactured at our Sinnar Plant in India which is an ISO 9001 accredited facility & houses a computer aided design manufacturing processing and testing infrastructure that ensures all products manufactured strictly comply with domestic and international standards and perform to the highest levels of safety reliability and life expectancy. Technology and Basic Construction : Amongst most electrical products Power Capacitors are highly susceptible to premature failures if improperly installed or if the application or load profiles are non linear or the system parameters are erratic. It is therefore of atmost importance that capacitors are designed to perform under such onerous conditions. Hence material selection quality inputs design manufacturing and processing parameters assume critical importance. ECOVAR High Voltage Power Capacitors are manufactured from raw material inputs sourced from the world s foremost manufacturers of plastic film dielectrics aluminum electrode foils and electrical insulating fluids. ECOVAR Capacitors generally utilize the following raw materials unless special end use applications necessitate use of alternative material : Dielectric : Electrical Grade Double Side Hazy Biaxially Oriented Polypropylene Film. Electrode : High Purity Soft Annealed Aluminum Foil. Impregnant : Phenly Xylyl Ethane (PXE) / Jarylec Non PCB Non Toxic Biodegradable. Housing : Stainless Steel / Mild Steel Sheet. Bushings : Soldered or Welded Brown / Gray Glazed Porcelain Insulators. Exterior finish : Etched Primer with Final Coats of Epoxy Paint. Visual comparison of Plain & Hazy PP Film Power Loss : ECOVAR Power Capacitors are uniquely designed to deliver optimun performance at very economic operating cost viz. power loss which are limited to maximum of 0.12 Watts / kvar on start up and 0.1 Watts / kvar after 500 hrs of operation. The extremely low watt losses contribute significantly in enhancing the capacitor life expectancy levels. Watt Loss & Capacitance Variation Graphs : Variation in losses (W/kvar) as a Variation in losses (W/kvar) as a Variation of capacitance C(μF) as
function of temperature function of operating time a function of temperature Fusing Techniques : Internal Fuse Design : ECOVAR Capacitor units are generally provided with internal fuses across each element for rendering internal protection to the capacitor unit in case of a fault occuring within the element winding. These fuses are designed on the basis of stored energy principle and coordinated to withstand all normal and some abnormal system overloads and disturbances and to render overall unit protection. (Refer to detailed internal fuse technical write up available on request). ECOVAR Capacitor units are also offered with option of conventional external fuses (Expulsion type / HRC type) depending on the unit kvar rating as also application and severity of protection required. Top Externally Fused Cell Internally Fused Cell Diagram Showing Internal Fusing Of Element In One Series Group : External Fuse Design :
An expulsion fusing system as used for protecting capacitors consists of three components which include the fuse tube / barrel the fuse link and the ejector spring. The proper operation of a fuse is dependent upon these components working in close harmony with each other. The illustrations below show the fuse assembly operation & visual indications of the fuse in fused and blown fuse position. Proper assembly of the fusing system is critical to the successful operation of the fusing system whereas incorrect installation may result in severe damage to the fuses the capacitors and / or capacitor bank. Expulsion fuse mounting arrangement Fuse link operation inside barrel Spring in Fused Position Spring in Blown Fuse (Indicating) Position Top Technical Comparison Between Internally & Externally Fused Capacitor Banks : Parameter Of Comparison External Fusing Internal Fusing Fuse isolates only the failed / faulty element No Yes
Capacitor unit is isolated on fuse operation Yes No Reduction in Bank output after fuse operation Considerable Negligible Reduction in unit life after fuse operation Unpredictable Marginal Bank with cells of higher kvar Out put No Yes Reliability of fuse co ordination / unbalance protection Un Predictable Case rupture protection Yes No Economy in cost of installation No Yes Vary Reliable Space requirement for installation Occupy More Space Occupy Less Space Visual indication of fuse operation Yes No Terminal to case insulation protection Yes No Consistency in fuse operation / protection No Yes Fuse is subject to routine electrical testing along with the unit Fuse is protected from environmental hazards No No Yes Yes Cost of structural steel & weight Higher Lower Convenience of assembly and connections Cumbersome Convenient External electrical clearances Are Less Are More Unit replacement in case of failure Convenient Cumbersome Types Of Mounting : Illustration showing Space saving & External Clearances
Capacitor banks can be offered with option of units mounted horizontally or vertically performance parameters remaining the same in either case. However for space saving compactness and better clearances in case of moderately sized or larger rated outdoor installations horizontal mounting is recommended. Internal or external fusing can be offered for both types of mounting options. Internally Fused Horizontally Mounted Units Externally Fused Vertically Mounted Units Pole Mounted Capacitors : Pole Mounted Capacitor Banks can be offered with power out puts from 300 kvar to 1200 kvar. These are operated with automatic vacuum / gas insulated switches and find applications on rural feeders where monitoring is difficult hence warrant a virtually maintenance free installation. These capacitors are usually offered with external fuses as bank and unit ratings are small. However dual fusing techniques are also offered as this helps not only in preventing case rupture due to dual protection but also ensure that the external fuses do not operate fictitiously as the internal fuses take care of most of the faults leaving the external fuse to operate only in case of a container to pack insulation failure / major external fault. Typical arrangement of externally fused pole mounted capacitor bank
General Arrangement Of ECOVAR Capacitor Unit : Bank Connections & Configurations : Capacitors Banks can be offered with option of the following configurations : 3 Ø Delta Connected. 3 Ø Y Connected. 3 Ø Y Y Connected. 1 Ø H Connected (Traction Duty Application for Railways). For Y / Y Y connected capacitor banks the star point is usually kept floating & used for sensing voltage & current unbalance. Accordingly suitable unbalance protection relays are provided on the control & relay panel to provide for tripping the bank on occurrence of severe unhealthy or unbalanced conditions. Below are connection diagrams that indicate various configurations & protection techniques. Also detailed herein are various protection schemes with switching & protective accessories. Delta Connected Capacitor Bank Y Connected Capacitor Bank With Voltage Unbalance Protection Y Y Connected Capacitor Bank With Current Unbalance Protection Capacitor Bank Control & Protection Schemes : Top
Universally practiced switching and protection schemes are designed and engineered to render total and thorough protection to the capacitor installation from internal abnormalities as also from external system disturbances or hazards. It is strongly recommended to provide over voltage under voltage over current earth fault ON time delay and unbalance protection to capacitor bank installations. Some typical protection schemes are shown in the schematic diagram below. Y Connected Capacitor Bank With Switching & Protection Equipment : Y Y Connected Capacitor Bank With Switching & Protection Equipment : Typical Layout Of An Outdoor Capacitor Installation :
Shown alongside is a typical layout of outdoor capacitor installation along with relevant switchgear and protection equipment. Reference standards : ECOVAR High Voltage Power Capacitors can be offered to comply with various international standards such as : IS : 13925 & IS : 12672 IEC : 60871 NEMA : CP 1 CEI : 33 7 VDE : 0560/4 BS : 1650 ANSI : IEEE Std 18 French : C 54102 CSA : C.22 2 No 190 AS : 2897 Range : Unit Voltage : 1.1 kv to 24 kv Unit Out put : 50 kvar to 600 kvar Bank Voltage : 3.3 kv to 145 kv Bank Out put : 300 kvar to 50 MVAr Basic Insulation Levels : The insulation levels for capacitor banks for various voltage networks are given in the table below : Basic Insulation Level of bank kv (SYSTEM) 12 24 36 72.5 123 145 Power Frequency withstand Voltage kv (RMS) 28 50 70 140 185 230 1.2/50 ms impulse withstand Voltage kv (PEAK) 75 125 170 325 450 500 Permissible Over Loads : Capacitor cells and banks may be required to perform under stressed and overloaded conditions for certain durations.
The permissible upper limits with respect to voltage and current overloading and the corresponding durations are : Current : 1.30 times rated current continuously. Voltage : 1.10 times VN for 12 hrs in a duration of 24 hrs. 1.15 times VN for 5 min. in a duration of 24 hrs. 1.30 times VN for 1 min. in a duration of 24 hrs.