high voltage direct current

High Voltage Direct Curent
www.HighVoltageDirectCurrent.com

Welcome to the
"High Voltage Direct Current"
Website

Supporting and Advancing the Smart Grid
Through our Following Products and Services:

Carbon Free Energy
Concentrating Solar Power Plants
Concentrating Photovoltaic Power Plants
Net Zero Energy Buildings
Pollution Free Power
Power Purchase Agreements
Solar Power Purchase Agreements
Solar Trigeneration Energy Systems

and the work and research of:

Pecan Street Project

Renewable Energy Institute

Austin, Texas

Please direct inquiries to:

Tel. (832) 758 - 0027

Email: info@HighVoltageDirectCurrent.com

What are the Advantages of High Voltage Direct Current Transmission Lines over the Standard AC Power Lines?

High Voltage Direct Current power lines have several distinct advantages over the typical AC power lines.

High Voltage Direct Current, or "HVDC" power lines has the ability to transmit large amounts of power over long distances with lower capital costs and much lower electrical losses than typical AC power lines.

Depending on the voltage level and construction details, losses for HVDC are about 3% per 1000 km.

High-voltage direct current transmission allows use of energy sources remote from load centers.

In a number of applications High Voltage Direct Current, HVDC is more effective and efficient than AC transmission lines.

Examples where HVDC is more effective, and efficient, than AC power lines, include the following:

* Undersea cables, where high capacitance causes additional AC losses.

* Endpoint-to-endpoint long-haul bulk power transmission without intermediate 'taps.'

* Increasing the capacity of an existing power grid in situations where additional wires are difficult or expensive to install.

* Allowing power transmission between unsynchronized AC distribution systems.

* Stabilizing a predominantly AC power-grid, without increasing maximum prospective short circuit current.

* Reducing line cost since HVDC transmission requires fewer conductors (i.e. 2 conductors; one is positive another is negative)

* Long undersea cables have a high capacitance. While this has minimal effect for DC transmission, the current required to charge and discharge the capacitance of the cable causes additional I2R power losses when the cable is carrying AC. In addition, AC power is lost to dielectric losses.

* High Voltage Direct Current transmission lines can carry more power per conductor, because for a given power rating the constant voltage in a DC line is lower than the peak voltage in an AC line.

* Increased stability of power systems - because High Voltage Direct Current transmission lines allow power transmission between unsynchronized AC distribution systems, it can help increase system stability, by preventing cascading failures from propagating from one part of a wider power transmission grid to another. Changes in load that would cause portions of an AC network to become unsynchronized and separate would not similarly effect a DC link, and the power flow through the DC link would tend to stabilize the AC network. The magnitude and direction of power flow through a DC link can be directly commanded, and changed as needed to support the AC networks at either end of the DC link. This has caused many power system operators to contemplate wider use of HVDC technology for its stability benefits alone.

Disadvantages of High Voltage Direct Current Transmission Lines

The required static inverters are expensive and have limited overload capacity. At smaller transmission distances the losses in the static inverters may be bigger than in an AC transmission line. The cost of the inverters may not be offset by reductions in line construction cost and lower line loss.

In contrast to AC systems, realizing multi-terminal systems is complex, as is expanding existing schemes to multi-terminal systems. Controlling power flow in a multi-terminal DC system requires good communication between all the terminals; power flow must be actively regulated by the control system instead of by the inherent properties of the transmission line.

We develop, acquire, own and operate Renewable Energy projects that include:

* Anaerobic Digesters

               * Utility Scale Wind Farms

               * Community Wind Farms

               * Wind power transmission lines

               * Electric power transmission lines

We provide assistance in the development, sale or trade of "greentags" from our renewable energy projects including;

We help clients by performing; Renewable Energy Feasibility Studies, Engineering Feasibility Studies and related consulting services that include Interconnection Agreements and Power Purchase Agreements.

* Some of the above information from the Department of Energy website with permission.

The Renewable Energy Institute is "Changing The Way The World Makes and Uses Energy by Providing Research & Development, Funding and Resources That Create Pollution Free Power, Carbon Free Energy & Renewable Energy Technologies"