Dynamic power and voltage regulator for an ac transmission line

• US 5,610,501 A
• Filed: 02/01/1995
• Issued: 03/11/1997
• Est. Priority Date: 02/01/1995
• Status: Expired due to Term

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Nelson, Robert J., Ramey, Donald G.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Berhane, Adolf
• Application Number:
  US08/380,991
• Time in Patent Office: 769 Days
• Field of Search: 323/205, 323/207, 323/208, 323/212, 307/102, 307/105, 363/34, 363/35, 363/37, 363/39, 363/40, 363/51, 363/95
• US Class Current: 323/207
• CPC Class Codes: H02J 3/1814 wherein al least one reactive element is actively controlled by a bridge converter, e.g. unified power flow controllers [UPFC]
• CPC Class Codes: Y02E 40/10 Flexible AC transmission systems [FACTS]

Abstract

Apparatus for providing reactive compensation and positive real power compensation in an ac electric power transmission system, utilizes a solid state inverter to inject a series compensation voltage into the transmission line at a controllable magnitude and a controllable phase angle between + or -90 electrical degrees relative to transmission line current. The positive real power needed by the inverter is drawn from the transmission line by a rectifier shunt connected to the line.

Claims

1. Apparatus for controlling an alternating current transmission system including a transmission line carrying alternating current at a selected transmission line voltage, and fundamental frequency said apparatus comprising:

switching power converter means generating an alternating voltage at said fundamental frequency of said alternating current with a controllable magnitude and a controllable phase angle between -90 electrical degrees and +90 electrical degrees relative to said alternating current to inject adjustable reactive compensation and adjustable positive real power;

means coupling said alternating voltage generated by said switching power converter means into said transmission line to inject said adjustable reactive compensation and adjustable positive real power into said transmission line; and

in series with said transmission line voltage; and

rectifier means connected in shunt to said transmission line and to said switching power converter means to provide said positive real power to said switching power converter means.

2. The apparatus of claim 1, wherein the rectifier means comprises a plurality of controlled rectifiers.

3. An apparatus for dynamically changing voltage in an ac transmission line or an ac distribution line carrying ac current at a fundamental frequency, said apparatus comprising:

switching power converter means generating an adjustable alternating voltage at said fundamental frequency of said ac current with a controllable magnitude;

means coupling said adjustable alternating voltage generated by said switching power converter means in series with said transmission line; and

rectifier means connected in shunt to said transmission line and connected to said switching power converter means to provide positive real power to said switching power converter means.

4. The apparatus of claim 3, wherein said switching power converter means comprises a multiple phase inverter.

5. A method for controlling an alternating current transmission system including a transmission line carrying alternating current at a selected transmission line voltage, and fundamental frequency said apparatus comprising:

generating an alternating voltage at said fundamental frequency of said alternating current with a controllable magnitude and a controllable phase angle between -90 electrical degrees and +90 electrical degrees relative to said alternating current to inject adjustable reactive compensation and adjustable real power;

coupling said alternating voltage into said transmission line to inject said adjustable reactive compensation and adjustable positive real power into said transmission line, and in series with said transmission line voltage; and

using a rectifier means connected in shunt to said transmission line to provide said positive real power for the step of generating an alternating voltage at said fundamental frequency of said alternating current with a controllable magnitude and a controllable phase angle.

6. The method of claim 5 wherein the controllable magnitude of the alternating voltage and the controllable phase angle of the alternating voltage to any phase angle between -90 electrical degrees and +90 electrical degrees relative to said alternating current effects independent regulation of transmission line series impedance and phase angle of said transmission line voltage.

7. The method of claim 5 wherein the controllable magnitude of the alternating voltage and the controllable phase angle of the alternating voltage to any phase angle between -90 electrical degrees and +90 electrical degrees relative to said alternating current effects dynamic regulation of said transmission line voltage in response to a dynamic variation in said transmission line voltage.

8. A method for dynamically changing voltage in an ac transmission line or an ac distribution line carrying ac current at a fundamental frequency, said apparatus comprising:

generating an adjustable alternating voltage at said fundamental frequency of said ac current with a controllable magnitude;

coupling said adjustable alternating voltage generated by said switching power converter means in series with said transmission line; and

using a rectifier means connected in shunt to said transmission line and connected to said switching power converter means to provide positive real power to said switching power converter means.