| Popis: |
This paper investigates the problem of the insensitivity of synchronous generators out of step protection when they are operating close to a High-Voltage Direct Current (HVDC) transmission system. Commercial out of step protection devices are based on the measurement of the impedance seen at the terminals of the generators and on the fact that this will be reversed when a loss of stability occurs. However, when these generators operate near an HVDC system, the out of step protection is desensitized, because the HVDC controls are able to maintain constant power when a loss of synchronism condition starts. As a consequence, the generators are exposed to serious damage. Our investigations also showed that the academy’s recent proposals to detect the out of step conditions were ineffective to solve the problem. Therefore, investigating the causes of this phenomenon and under what conditions it occurs is fundamental to develop efficient methods to solve it. |
