Novel High Voltage Cryogenic Breaks

The US Department of Energy (DOE) is actively seeking to develop new and improved Cryogenic High Voltage Breaks (CHVBs) that are used to electrically isolate cryogenic devices and equipment (e.g. accelerator and fusion energy magnets, electrical power equipment, etc.) operating at High Voltages (HV) from nearby grounded components and structures (e.g. cryogenic piping and refrigeration). The CHVB’s used in particle accelerators and fusion energy devices have many stringent technical requirements and must be capable of withstanding high electric field (E-field) stresses, have high voltage creep strength, support high mechanical stresses (both tensile and compressive), withstand high internal gas pressures at cryogenic temperatures, and sustain radiation doses in excess of 50 MGyi via high-energy particle bombardment, all while maintaining ultra-high vacuum (UHV) conditions. With these ever increasingly extreme environmental conditions and structural loading requirements, modern state of the art ceramic based CHVB’s with metal-glass interfaces often offer subpar performance metrics particularly in terms of reliability from thermal cycling stresses and voltage creep. However, recent advances in material composition, dielectric surface treatments, and the possibility of introducing Additive Manufacturing (AM) offer the potential for the improved HV performance at lower fabrication costs. Energy to Power Solutions (e2P) of Tallahassee, FL in collaboration with Argonne National Laboratory proposes two novel proprietary approaches to the design and fabrication of these CHVB’s based upon low cost 3-d printed structures. The underlying based structures of our proposed 3-d printed materials are: a) mechanically strong and able to withstand high gas pressure at cryogenic temperatures, b) radiation hard, and c) cryogenically compatible down to 1.9 K after repeated thermal cycling. e2P proposes to modify both the macroscopic and microscopic structure of the CHVB’s surface, in order to enhance their performance in terms of voltage creep strength per unit length, thus making them more compact than an existing metal-ceramic or metal-glass CHVB. In addition, by using a composite multi-layer 3-d printing approach that employs a “graded dielectric strength,” our first of a kind 3-d printed structure would also have superior voltage breakdown strength against HV puncture when compared to commercial CHVB. A key enabling feature of our proposed CHVB technology will be the development of a cryogenically compatible, radiation hard, hermetic seal that mates the 3-d printed base structure to the desired metal flange interface. High voltage insulators are needed in nearly every power electronics and electric power applications. The ability to fabricate via AM more complex high quality HV bushings and insulators using the proposed EFSR technology could have a tremendous economic incentive for the developing entity.