3/18/2023 0 Comments Expand inmrSections glued and cured to achieve required length of insulator.ĬLICK TO ENLARGE Glued joint on 1000 kV OIP bushing. One of the challenges still ahead for Zintl is expanding the kiln with a flat roof that will eventually allow four pieces to be fired over the typical 60-hour cold-to-cold cycle, instead of the current two. Moisture content of pugs during electrical heating falls to required level of 17 percent.Īfter glazing and firing, individual sections are attached using special epoxy glue that is so strong that the porcelain will typically break at other locations during mechanical tests to ultimate failure. About three days of continuous current is needed to remove only 2 percentage points of moisture and bring the moisture content of the pug to 17 percent, deemed ready for turning. Thermometers placed along the surface of each 1.6 m pug monitor temperature. Note special storage tents on top left photo that ensure even moisture content in each brick.Īfter extrusion, the next key step is drying, which is accomplished with assisted electrical heating to some 45☌. In the past, this was up to 80 percent long rods but will now change to 70 percent hollow core units, with the remainder divided about equally between long rods and station posts.ĬLICK TO ENLARGE Bricks fed into extruder. Along with this expansion in production capabilities has been a general re-focus of the plant’s overall product mix. This contrasts with the previous limitation of up to a maximum of 750 mm diameter, suited for insulators up to 765 kV. Mike Zintl, Sonneberg’s Managing Director, explains that the new extruder put into service there in recent weeks will allow production of pugs with maximum diameter of 1.4 m that will serve applications up to as high as 1100 kV. Shed tip-to-tip diameter will be 1.2 m after shrinkage during firing. Parts for GIS bushings for application at 1100 kV, made on new extruder, that will reach 11.5 m length. It was with such considerations in mind that PPC Insulators has undertaken a number of significant investments in its factories, including about Euros 2.5 million devoted specifically to purchase and install a massive new extruder at the Sonneberg plant. Instead, as voltages levels increase, he points out that demand for stringent quality and control grows as well. But Welsch argues that modern requirements for highly engineered products with specific shed profiles and forms demonstrate that this is actually not the case. One of the perceptions among some users these days is that electrical porcelain has become a commodity to be purchased mainly on the basis of price and delivery. The remaining plants either focus on applications for voltage levels below 245 kV or serve mainly regional markets. At the same time, equipment from the closed Austrian plant has been re-located to Slovakia, allowing that facility to expand its production devoted exclusively to solid core station posts. In the process, the factory in Sonneberg has now been designated the company’s center of competence for hollow core insulators for applications up to the highest transmission voltages. PPC Insulators too has had to re-structure, shutting production facilities in Austria and Sweden and shifting their capacity to plants in Germany, Slovakia, Thailand and Brazil. Industry overcapacity in electrical porcelain has required plant closures and some competitors have left the field entirely. INMR visited the plant last autumn to report on the new equipment and to discuss the drivers behind it.ġ000 kV bushing ready for final testing demonstrates growth in demand for highly engineered porcelain of great dimensions.Īccording to Sales & Marketing Director, Wolfgang Welsch, recent years have witnessed a consolidation within the porcelain insulator industry that serves an annual global market for MV & HV applications he estimates at about US$ 2 billion. It is against this backdrop that PPC Insulators recently made a substantial investment at its plant in Sonneberg, Germany. At the same time, the growing number of HVDC and UHV AC and DC projects has also created new opportunities to supply units with greatly increased dimensions as well as performance requirements. The past two decades have seen the marketplace for high voltage porcelain insulators impacted by intense global competition as well as a serious challenge from hollow core composite technology.
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