August 4, 2017
Taiyo Nippon Sanso Corporation
Sales Agreement Signed in Russia for Turbo Refrigerator
for High Temperature Superconducting Power Application (NeoKelvin®-Turbo 2kW)
Taiyo Nippon Sanso Corporation (“TNSC”) has announced that it has signed an agreementwith SuperOx Japan LLC (President: Sergey Lee, “SuperOx Japan”) to sell three units of theturbo-Brayton [Note 1] refrigerator NeoKelvin®-Turbo 2kW for use in the superconducting
fault current limiter equipment of UNECO, an electric utility in Moscow. NeoKelvin®-Turbo2kW is able to cool superconducting power equipment to -200°C or lower by using neon gas
as the working fluid.
1. Background to Signing the Agreement
In recent years, as demand for electricity has grown, Moscow has faced the need to increase
the capacity of circuit breakers in order to counter fault currents (particularly, short circuitaccidents) in the power grid. However, the high cost of these refurbishments had presented anissue for the city.
SuperOx, a Russian high temperature superconducting wire manufacturer, and its Japaneseaffiliate SuperOx Japan, had proposed that UNECO introduces superconducting fault current
limiters (“SFCLs”) [Note 2] to replace circuit breakers, because this approach would reduce
the refurbishment costs while providing superior operating performance. From 2015, UNECO
and the aforementioned two companies have been jointly making preparations to introduce
SFCLs. As a result, UNECO has decided to install and implement trial operations of SFCLs
for a 220 kV line at its substation in Moscow.
The operation of SCFLs requires the stable maintenance and control of a low temperatureenvironment of -200°C. To meet this requirement, TNSC’s turbo-Brayton refrigerator forhigh temperature superconducting power application (NeoKelvin®-Turbo 2kW) has been
adopted for use.
TNSC has signed an agreement to sell three units of NeoKelvin®-Turbo 2kW to SuperOx
Japan. SuperOx and SuperOx Japan will integrate the SCFLs into the system, and install thesystem at the UNECO substation in Moscow.
2. Outline of NeoKelvin®-TurboTNSC has developed a turbo-Brayton refrigerator (NeoKelvin®-Turbo 2kW) with the coolingcapability of 2kW by using neon gas as the working fluid, as part of the “TechnologicalDevelopment of Yttrium-based Superconducting Power Equipment (2008 – 2012),” a project
led by the New Energy and Industrial Technology Development Organization (NEDO).
TNSC commercialized NeoKelvin®-Turbo 2kW in May 2013.

Moreover, in 2016 TNSC commercialized NeoKelvin®-Turbo 10kW, a unit with acooling capability 5 times greater than the 2kW model. Both the 2 kW and 10 kW models areundergoing extensive trial operations worldwide for the cooling of high temperature
superconducting power transmission cables.
(1) Feature of machine1）We have adopted active magnetic bearings for the turbo-machine to compress andexpand neon gas as it can be operated without mechanical contact by floating the main
shaft in the air to eliminate the maintenance.
2）We have adopted an energy efficient structure in which the power generated by theexpander is returned to the compressor as regenerative power.
3）We have adopted a high precision operating temperature control method based on
adjusting the rotational speed of the compressor.
(2) Specifications of the 2kW model
Refrigeration temperature: 70K (-203ºC) (Temperature of liquid nitrogen at the outlet ofthe refrigerator)
Refrigeration capability: 2 kWPower source voltage:
3-phase alternating current, 400 V
Electricity consumption: 55 kW
Cooling water:
250 L/min
3. Developments going forward
SFCLs offer a competitive price and superior operating performance compared withlarge-capacity circuit breakers. In fact, SFCLs are able to apply a limit to fault currents 100
times faster than large-capacity circuit breakers. Therefore, SFCLs can more reliably prevent
large fault currents from negatively impacting sound equipment. For these reasons, demandfor SFCLs is expected to increase on a global basis. In step with this global growth in demandfor SFCLs, TNSC will take proactive steps to ensure that its NeoKelvin®-Turbo units areadopted for use.
< Glossary>[Note 1] Turbo-Brayton refrigerator
This is a refrigerator to generate cold by four processes ((1) Adiabatic compression, (2)Isobaric cooling, (3) Adiabatic expansion, and (4) Isobaric heating). The neon gas that iscompressed by the turbo compressor ejects the compression heat to the atmosphere, then it isexpanded under adiabatic conditions by a turbo expander to lower the temperature of the neongas. After that, it absorbs the surrounding heat, and it is returned to the inlet of the turbocompressor. In the case of an actual refrigerator, a heat exchanger is inserted between theturbo compressor and the turbo expander to collect the cold generated at the expander.

[Note 2] Fault Current Limiter
This is one type of safety equipment designed to reduce the overload current swiftly at
accidents caused by short-circuit / electric leakage in the electricity transmission anddistribution system. Notably, superconducting fault current limiters have outstanding
responsiveness to fault currents because they make use of extremely rapid superconducting
phase changes.

Exterior of the NeoKelvin®-Turbo 2kW machine