Technical support

Fields of our research Next Generation Power Grid and Substation Laboratory Technical support

Technical support for selecting the routes for the No. 3 HVDC (mainland ~ Jeju) underwater cable.

The Power Transmission and Substation Laboratory provided technical support in reviewing the influence of the routes of the No. 3 HVDC underwater cable between the mainland and Jeju being near No. 1 HVDC electrode site. There are Haenam ~ Jeju HVDC and Jindo ~ Jeju HVDC between the mainland and Jeju island, which have been in operation. While the Jindo-Jeju HVDC is based on a double -bipole that is composed of four DC cables, thus without any electrode sites, the Haenam ~ Jeju HVDC is of a bipole structure that is composed of two cables. For this reason, there is one electrode site in Haenam and Jeju, each, for the monopole operation of the line. The review on the electrical influences between electrode sites and cables through the technical support from the laboratory, it was shown that even if the route of the No. 3 HVDC line is within 10km from an electrode site, the influence on the corrosion of the cable armor is insignificant. According to the result, it is only when the route of the HVDC cable and an electrode site is within 1 to 2 km from each other that a corrosion level based on the detailed modeling of the DC cable and the electrode site and the electrode site operating scenario needs be evaluated.

[ the routes under review of No.3 HVDC underwater cable ]

Tuning and Performance Test for the No. 3 an $ Dangjin Thermal Power Plant System Stabilizing Equipment

The Power Transmission and Substation Laboratory is providing technical services to fine-tune the PSS parameters to ensure that the PSS, or Power System Stabilizer has enough damping capability. In accordance with the ‘Criteria for Maintaining the Reliability of a Power System and Power Quality’, it is required to tune the PSS and perform a performance test on it when there is a change with the power generator or other related controllers. The results of such a test must be reported to Korea Power Exchange. Here, the AVR (Automatic Voltage Regulator) of Unit 3 and 4 of Dangjin Thermal Power HQ has been replaced with a South Korean-made AVR, and the lab provided technical support to re-tune the PSS, which is an auxiliary controller for the AVR. The tuning and performance testing technology for PSS is only available with the Performance of KEPCO Research Institute and Korea Electrotechnology Research Institute. As we developed the technology for which we had to rely on foreign technology, we have been saving billions of won in each year since 2005.

[ Tuning and Performance Test for Power System Stabilizing Equipment ]

Tuning and Performance Test for Power System Stabilizing Equipment
the exterior of SCB-500
display of AVR/PSS

Technical Support for Addressing the Failure of a 345kV reactor

The Power Transmission and Substation Laboratory is providing technical support for identifying the causes of failures of high-frequency circuit breakers for 345kV reactors. Including the circuit breakers for high-capacity underground cables, the circuit breakers for reactors control the voltage of the systems based on the changes in the load. Therefore, their frequency of switching actions is high, and so is their rate of failure. The chance of electrical breakdown proceeding to a failure is so high, as the circuit breakers for reactors are exposed to vibratory circuit switching overvoltage each time they operate, there are 13 failure records in 51 substations with reactors. Therefore, it is necessary to develop an innovative solution to prevent such a failure. One of the possible options is to control the circuit-breaking phases in an optimized manner. In response to the request from North Gyeonggi Regional HQ that experienced a circuit breaker failure, the lab provided technical support to identify whether there is a restrike during the switching operations of the reactors and measure the volume of the switching overvoltage during these operations. The laboratory built a custom sensor to check for restrikes. And, the technical support provided an opportunity to start an R&D project to measure the volume of the switching overvoltage.

[ Technical Support for the restrike of a 345kV reactor and the measurement of overvoltage ]

Technical Support for the restrike of a 345kV reactor and the measurement of overvoltage
Technical Support for the restrike of a 345kV reactor and the measurement of overvoltage