Abstract: The present disclosure provides a parameter design method for a series passive impedance adapter applicable to a VSC-HVDC transmission system, to resolve the technical problem that high-frequency resonance may occur when impedance of a VSC-HVDC transmission system is mismatched with that of a sending-end or receiving-end grid. A parameter design goal of the present disclosure is that reactive power consumed by a series passive impedance adapter is not more than A times rated power of a converter, and a loss of the series passive impedance adapter in a fundamental wave is B times the rated power of the converter. The parameter design method for a series passive impedance adapter applicable to a VSC-HVDC transmission system in the present disclosure can realize a positive impedance characteristic within a concerned frequency band and completely eliminate a risk of harmonic resonance.

Abstract: The present utility model provides a fan cover shell and an air conditioning unit having the same. The fan cover shell includes an outer frame; multiple annular auxiliary reinforcement ribs, arranged from the center of the fan cover shell towards the outer frame; and multiple main reinforcement ribs, respectively extending from the center of the fan cover shell to the outer frame and intersecting with the auxiliary reinforcement ribs to form multiple ventilation grills; the main reinforcement rib forms a multi-section curve, and any adjacent curves of the multi-section curve bend towards a reverse direction. According to the fan cover shell of the present utility model, a better air guide effect is achieved by optimizing the main reinforcement ribs.

Abstract: The embodiments herein relate to a method in a network device. In one embodiment, there proposes a method in a network device, comprising: determining a classification to which a route belongs based on one or more classification criteria; determining, based on the classification to which the route belongs, a detection mechanism for detecting whether the route is an abnormal route; detecting whether the route is an abnormal route using the determined detection mechanism. With the embodiments herein, the abnormal routes, especially the black hole routes, can be automatically detected and resolved in real time.

Abstract: The utility model relates to a noise reduction device for an outlet side of a fan, and a heat exchange system including the noise reduction device. The noise reduction device includes: a connecting portion configured to be connected with at least a part of the air duct cover, and form an accommodation space communicating with an airflow on the outlet side via at least one of the through holes; and at least one first chamber and/or at least one second chamber, the first chamber being located in the accommodation space and filled with a sound-absorbing material, and the second chamber being located in the accommodation space and configured as a resonant noise-reduction cavity. The utility model is easy to manufacture, install and maintain, the noise reduction effect is obvious, and therefore the utility model has significant practicability.

Abstract: The utility model relates to a noise reduction device for an outlet side of a fan, and a heat exchange system including the noise reduction device. The noise reduction device includes: a connecting portion configured to be connected with at least a part of the air duct cover, and form an accommodation space communicating with an airflow on the outlet side via at least one of the through holes; and at least one first chamber and/or at least one second chamber, the first chamber being located in the accommodation space and filled with a sound-absorbing material, and the second chamber being located in the accommodation space and configured as a resonant noise-reduction cavity. The utility model is easy to manufacture, install and maintain, the noise reduction effect is obvious, and therefore the utility model has significant practicability.

Abstract: The embodiments herein relate to a method in a network device. In one embodiment, there proposes a method in a network device, comprising: determining a classification to which a route belongs based on one or more classification criteria; determining, based on the classification to which the route belongs, a detection mechanism for detecting whether the route is an abnormal route; detecting whether the route is an abnormal route using the determined detection mechanism. With the embodiments herein, the abnormal routes, especially the black hole routes, can be automatically detected and resolved in real time.

Abstract: The present utility model provides a fan cover shell and an air conditioning unit having the same. The fan cover shell includes an outer frame; multiple annular auxiliary reinforcement ribs, arranged from the center of the fan cover shell towards the outer frame; and multiple main reinforcement ribs, respectively extending from the center of the fan cover shell to the outer frame and intersecting with the auxiliary reinforcement ribs to form multiple ventilation grills; the main reinforcement rib forms a multi-section curve, and any adjacent curves of the multi-section curve bend towards a reverse direction. According to the fan cover shell of the present utility model, a better air guide effect is achieved by optimizing the main reinforcement ribs.