Global High-Voltage Direct Current Transmission Systems Market By Type (Below 500 MW , 501-1000 MW , 1001-1500 MW , 1501-2000 MW , and Above 2000 MW), By Application (Underground Power Transmission , Grid Interconnection , and Offshore Power Transmission), By Region, and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2020-2029