SwePol

SwePol is a 254.05-kilometre (157.86 mi)-long bipolar high-voltage direct current (HVDC) submarine cable between the Stärnö peninsula near Karlshamn, Sweden, and Bruskowo Wielkie, near Słupsk, Poland.[1]

SwePol
Stärno Bruskowo Wielkie Location of SwePol
Location
Country	Sweden, Poland
Coordinates	54°30′7.6″N 16°53′28.4″E 56°09′10.7″N 14°50′29.4″E
General direction	north–south
From	Stärnö Static Inverter Plant, Sweden
Passes through	Baltic Sea
To	Bruskowo Wielkie Static Inverter Plant, Poland
Ownership information
Owner	Svenska Kraftnät, PSE-Operator
Construction information
Manufacturer of conductor/cable	ABB
Manufacturer of substations	ABB
Commissioned	2000
Technical information
Type	subsea cable
Type of current	HVDC
Total length	254 km (158 mi)
Power rating	600 MW
AC voltage	400 kV (both ends)
DC voltage	450 kV

SwePol is a high voltage cable with a cross section of 2,100 square millimetres (3.3 sq in). It runs for 222 kilometres (138 mi) as underground cable from Stärno HVDC Station to the shore of the Baltic Sea. The 239.28 kilometres (148.68 mi) long submarine cable comes ashore in Poland near Ustka at 54°34′25″N 16°46′57″E and runs underground for the remaining 12.55 kilometres (7.80 mi) to Bruskowo Wielkie HVDC Static Inverter Plant.

Unlike other monopolar HVDC schemes, Swepol uses a metallic return consisting of 2 cables with 630 square millimetres (0.98 sq in) sections for the submarine portion of the line, and a single cable with 1,100 square millimetres (1.7 sq in) sections for the land portions.

Both stations use air-core inductance smoothing rectifiers of 225 mH and a weight of 27.5 tonnes, with filters for the 11th, 13th, 24th, and 36th harmonics. Each filter consists of a coil and a capacitor switched in row. The filters for the 11th and 13th harmonics are adjustable. The filters deliver a reactive power of 95 Mvar. Additional 95 Mvar reactive power is delivered by a capacitor bank. Each station's static inverter, which is switched as a 12-pulse thyristor bridge, consists of 792 thyristors arranged in three 16 metres (52 ft) high towers installed in a valve hall.

The SwePol link was inaugurated in 2000 and can transmit up to 600 MW power at a voltage of 450 kV. It was initially owned and maintained by SwePol Link AB, a company jointly owned by the state-owned Swedish power company Svenska Kraftnät (51%), Vattenfall (16%), and Polish transmission system operator PSE-Operator (33%), but the company was liquidated and the cable was acquired by Svenska Kraftnät for the Swedish and PSE-Operator for the Polish part of the cable.

Since coming online, 11 instances of cable damage have occurred: one on the high voltage line and 10 on the return cable. Causes have included ship anchors, fishing nets, fire, and grid power disturbances. On February 14, 2005, the smoothing reactor at the HVDC station at Bruskowo Wielkie was destroyed by fire. Repairs took 20 hours.

Initially SwePol was used to export electricity to Poland only.

From January to October 2020 Poland exported 1,225.9 GWh of electricity and imported 12,573.1 GWh compared to 872.8 GWh and 9,326.7 GWh in the same period 2019. The largest import was from Germany 3,222.2 GWh, Sweden 3,195.9 GWh and the Czech Republic 2,561.5 GW.[2] Poland’s power market will face a supply squeeze from 2025, when a tightening of EU rules on plants’ CO2 emissions will force nearly 5 GW of thermal capacity out of the system, the nation’s TSO has warned.[3]