HVDC Rio Madeira Grouding Electrode

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The HVDC (High Voltage Direct Current) grounding electrode of the Rio Madeira - Bipole 1 is an essential component of the HVDC transmission system that connects the hydroelectric power plants of the Madeira River (Santo Antônio and Jirau, in Rondônia) to the electrical system of southeastern Brazil, with a terminal point in Araraquara (SP).

Context of the Rio Madeira - Bipole 1 Project

Length: Approximately 2,375 km.
Voltage: ±600 kV (positive and negative with respect to ground).
Transmission capacity: Up to 3,150 MW.
Type: Bipole HVDC system, with converters in Porto Velho (Rondônia) and Araraquara (São Paulo).
Entered operation: 2013.
What is a Grounding Electrode?

A grounding electrode in HVDC systems is an installation designed to allow the closing of the electrical circuit in case of a fault in one of the system's poles or during monopolar operation (when one pole is out of service). The electrode injects direct current into the ground, completing the electrical path through the earth.

Grounding Electrode of Bipole 1

In Bipole 1 of the Rio Madeira system, there are two grounding electrodes, one at each end of the system:

Porto Velho Electrode (Rondônia):

Located about 30-50 km from the converter station.
Generally installed in areas with low population density to minimize electrochemical effects and stray currents (which can damage metallic pipelines, for example).
Araraquara Electrode (São Paulo):

Similarly located at a safe distance from the converter station and urban areas.
Technical Characteristics of the Electrode

Type: Can be horizontal (buried rings or lines) or vertical (deep rods).
Material: Steel or copper-clad conductors, designed to withstand high direct currents for long periods.
Typical current: Can reach thousands of amperes (usually up to 3,000 A or more in fault conditions).
Auxiliary equipment: Corrosion, soil resistivity, and temperature monitoring system.
Importance

Ensures the operational reliability of the HVDC system.
Allows safe operation in monopolar mode if one pole is inoperative.
Designed to minimize environmental impacts and interference with nearby installations.