HVDC & SVC Modernization

Tailored HVDC and SVC upgrade solutions

Southern States provides customized upgrade solutions for transmission and industrial assets that have been in service for decades.

Our portfolio covers both High Voltage Direct Current (HVDC) and Static Var Compensator (SVC) systems, focusing on life extension, modernization, and performance improvements.

HVDC Life Extension

Southern States delivers targeted upgrades for HVDC transmission systems, extending the life of critical assets while improving reliability and efficiency. Our solutions focus on modernizing thyristor valves and cooling equipment with field-proven retrofits that reduce maintenance, increase system availability, and address component obsolescence.

Key Benefits:

Enhanced reliability with modern thyristor valve assemblies
Improved thermal stability and reduced maintenance with advanced cooling systems
Obsolescence mitigation by replacing unsupported OEM components
Extended lifetime of HVDC links, maximizing original capital investment
Lower risk of prolonged outages on critical interconnections

Our Capabilities:

Repair and rebuild of thyristor valve power modules
Upgrade from parallel small thyristors to single large-area devices for higher margins and efficiency
Refurbishment of heatsinks, clamping systems, and gate drives
Repair or replacement of VBO circuitry, snubber networks, and grading components
Modernization of valve triggering with indirect light-triggered thyristor (SLTT) technology
Fiber optic link replacement and refurbishment of transmitter/receiver circuitry
Supply of dynamically matched thyristor sets (40 mm, 53 mm, 77 mm) and pulse transformer assemblies

SVC Upgrades

Southern States offers two distinct paths for extending or upgrading Static Var Compensator (SVC) systems. Operators can choose between traditional life extension of existing equipment or upgrading to STATCOM technology while reusing the SVC’s passive components.

HVDC Life Extension

Key Benefits:

Enhanced reliability with modern thyristor valve assemblies
Improved thermal stability and reduced maintenance with advanced cooling systems
Obsolescence mitigation by replacing unsupported OEM components
Extended lifetime of HVDC links, maximizing original capital investment
Lower risk of prolonged outages on critical interconnections

Our Capabilities:

Repair and rebuild of thyristor valve power modules
Upgrade from parallel small thyristors to single large-area devices for higher margins and efficiency
Refurbishment of heatsinks, clamping systems, and gate drives
Repair or replacement of VBO circuitry, snubber networks, and grading components
Modernization of valve triggering with indirect light-triggered thyristor (SLTT) technology
Fiber optic link replacement and refurbishment of transmitter/receiver circuitry
Supply of dynamically matched thyristor sets (40 mm, 53 mm, 77 mm) and pulse transformer assemblies

Option 2: Upgrade to STATCOM

Scope Includes:

Integration of STATCOM active compensation with existing SVC filters and capacitor banks
Modular STATCOM design adapted to existing infrastructure
Optimized footprint with simplified future expansions

Benefits:

Faster, more dynamic grid response compared to SVC
Superior performance for flicker reduction, harmonics, and rapid load changes
Cost-efficient by leveraging existing passive equipment
Long-term solution aligned with modern grid requirements

Consideration	SVC Life Extension	Upgrade to STATCOM
Scope	Replacement/refurbishment of thyristor valves, cooling systems, filters, and auxiliaries	Replace active stage with STATCOM while reusing SVC passive filters and capacitor banks
Performance	Restores original SVC performance, maintains steady reactive power support	Next-generation dynamic response, superior flicker and harmonic control, supports fast-changing loads
Obsolescence	Mitigates risk by replacing discontinued OEM parts	Eliminates reliance on legacy valve technology, transitions to modern STATCOM platform
Investment	Lower CAPEX than new build; cost-efficient for extending asset life	Higher CAPEX than refurbishment, but leverages existing passive equipment for savings
System Life	Extends SVC operation for another lifecycle period	Provides long-term solution aligned with modern grid requirements