Korkeajännitetasavirtasiirto

Korkeajännitetasavirtasiirto, often abbreviated as HVDC, is a technology for transmitting electrical power using direct current (DC). This contrasts with the more common high-voltage alternating current (HVAC) systems used for power transmission. HVDC systems are particularly advantageous for long-distance power transmission and for interconnecting asynchronous AC grids.

The fundamental components of an HVDC system include converter stations at both the sending and receiving ends. These stations convert AC power to DC for transmission and then convert the DC power back to AC for distribution. The conversion process typically involves thyristor-based or diode-based rectifiers and inverters.

HVDC offers several benefits over HVAC. For long distances, HVDC can be more economical due to lower transmission losses and the absence of reactive power compensation requirements. It also has a higher power transfer capability for a given conductor size. Furthermore, HVDC links can efficiently connect AC grids with different frequencies or phase angles, acting as asynchronous ties. This capability is crucial for integrating different national or regional power systems.

However, HVDC systems also have drawbacks. The converter stations are complex and expensive, making them less cost-effective for shorter distances where HVAC is sufficient. Additionally, HVDC transmission requires significant land area for the converter stations and rights-of-way for the transmission lines. The DC lines themselves can also be a source of electromagnetic interference, although advancements in technology have mitigated this issue.