The transmission system is more stable thanks to the regulating transformers

5/30/2017

Since mid-January, two PSTs (Phase Shifting Transformers – transformers with phase angle regulation) have been regulating electricity flows from the eastern part of Germany. This contributed to the transmission system operator not having to use other costly remedial measures for maintaining the stability of the network and saving up tens of millions CZK. In
the first quarter, the YoY profit of ČEPS, a.s. increased by CZK 235 million. The Company has thus achieved the profit before tax of CZK 948 million.

For now, dispatchers regulate electricity flows on one of the two 400 kV lines connecting
the system with the eastern part of Germany. The Czech transmission system operator is planning to put the two remaining machines in operation by the end of June. Eventually, two PSTs will be connected in parallel on each of the lines. The last machine arrived in
the substation Hradec u Kadaně in the middle of March. The device was then assembled and connected to the substation equipment; testing and test operation are currently underway. Only after that the operation of the transformer will be included in the energy management system.

“The regulatory scope of the first two units has been unloosen gradually. In the first quarter,
the transformers were used during 48 days,” says Jan Kalina, Chairman of the Board of
ČEPS, a.s.

Phase-shifting transformers are machines that are used to control the power flow of real power through manipulation of the phase angle of the voltage between the transmitting end and
the receiving end of the line. Put simply, if we imagine the transmission system as a reservoir with many tributaries and distributaries, the PST works as a valve, which reduces, or increases the flow in the given distributary. Reducing the flow on one power line results in redistribution of flows in the entire interconnected system. Since electricity takes the path of least resistance, part of the flows will move to other power lines with more available capacity, thus eliminating possible overloads in the transmission network. The goal of PST transformers is not to prevent electricity flowing through our transmission system. ČEPS aims to transfer the maximum amount of electricity, but safely, without compromising the reliability of the power supply in the Czech Republic. And this is what this special type of transformer has to offer.

“Setting up the regulatory parameters of the PSTs is coordinated with foreign partners at
the pre-launch phase with the primary objective of ensuring the operational reliability of electricity networks throughout the region,” adds Kalina.

In January, the dispatchers recorded a historic high load on the electrical power system. It went up to 11,769 MW. It happened on Tuesday afternoon, January 24. The previous record was from February 7, 2012, when the load reached 11,296 MW.

“The new historical maximum was reached due to a very cold weather. The average monthly temperature was almost 5 degrees lower than the temperature normal for January,” explains Miroslav Šula, Head of the System Operation Management section of ČEPS, a.s.

One of the key investment projects of this period was the construction of a new 420 kV Vernéřov substation. This substation is built on the basis of the request of the company ČEZ Distribuce for ensuring the reserved supply and output for the area, and also a request for the connection of
the generating capacity of the projected wind farm in the region of Chomutov. It is located northwest of the town of Kadaň in the Ústí Region. 

The Czech transmission system is being enhanced also thanks to EU grants. Under programs of the European Commission, the ČEPS Company has to date obtained over four million euros for financing of projects of common interest.

“It can be concluded that the investment plan of the ČEPS Company contains projects that ensure reliable operation of the transmission system of the Czech Republic, while also contributing to the fulfillment of European objectives with regard to the safety of the whole interconnected system,” says Kalina.

The total of 16,933 GWh of electric energy was transferred in the reference period.

Press Release