RDCPE's experts in converter and superconductor technologies with prior experience in development and manufacturing of 30 m and 200 m high-temperature superconductor AC cables are currently engaged in endurance testing of the cable and Russian-made cryogenic system in collaboration with other partner companies. Development of superconductor DC cable line (1,500 meters, 20 kV, 50 MVt) with a DC link is also currently underway.

The advantages of the aforementioned cable line compared to AC-based solutions include the following:

• transmission of power with minimal losses;
• limited short circuit current;
• regulation of reactive power;
• linkages of different energy systems, including those operating with different frequencies.

In addition, high-temperature superconductor technologies offer the following social and economic advantages:

• reduced land requirements (by a factor of 3 to 4) in major cities as overhead power lines are replaced by superconductor cables;
• diminished electricity losses in grid elements by a factor of 2 to 3;
• minimized environmental impact resulting from lowered electromagnetic impact;
• extended design life (by 1.5) of the equipment due to reduced short circuit currents;
• improved stability and reliability of energy systems;
• higher quality of electricity provided for consumers;
• better fire safety (no-oil technology).

RDCPE operates an up-to-date testing center for high-technology superconductor equipment under the conditions closely resembling real-life operations.

Background

High-temperature superconductor technologies can be utilized in urban power supply systems through DC and AC cable lines.

HTSP AC cable lines are best suited for scenarios where high power supply flows with low voltage (10 to 20 kV) have to be distributed directly from generator voltage or substation busbars. This also implies that step-up or step-down transformer substations (for instance, 20/110 kV or 110/20 kV) are not available and overhead power lines either cannot be built or are being replaced.

DC high-temperature superconductor cables fulfill similar functions and are also able to serve as short-circuit current arrestors. They can also fulfill the function of power flow management, including reverse power flow.

Therefore, DC high-temperature superconductor cables are an optimal solution when substantial power flows have to be conveyed at low voltage and power flow management function is important. These issues are a well known and frequent occurrence in power supply systems of Moscow, St. Petersburg and other urban centers. Plans are underway to build a pilot cable line in one of St. Petersburg’s districts where the problem of increased reliability of power supply combined with restricting short circuit currents is particularly acute.