Interconnection system for transmitting power between electrical systems

• US 6,741,485 B1
• Filed: 03/31/1997
• Issued: 05/25/2004
• Est. Priority Date: 04/21/1995
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Larsen, Einar V., Runkle, Mark A.
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US08/828,502
• Time in Patent Office: 2,612 Days
• Field of Search: 363/170, 363/171, 363/174, 363/175, 323/201, 323/348, 307/47, 307/67, 307/68, 318/150, 318/158, 318/700, 318/723
• US Class Current: 363/170
• CPC Class Codes: H01F 38/18 Rotary transformers
• CPC Class Codes: H02J 3/06 Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
• CPC Class Codes: H02J 3/1828 with stepwise control, the possibility of switching in or out the entire compensating arrangement not being considered as stepwise control
• CPC Class Codes: H02J 3/34 Arrangements for transfer of electric power between networks of substantially different frequency
• CPC Class Codes: H02K 47/22 Single-armature frequency converters with or without phase-number conversion
• CPC Class Codes: H02P 2101/10 for water-driven turbines
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

An electrical interconnection system (100) comprises a variable frequency rotary transformer (102) and a control system (104). The control system (104) adjusts an angular position of the rotary transformer (102) so that measured power (P₁) transferred from a first electrical system (22) to a second electrical system (24) matches an inputted order power (P₀). The rotary transformer (102) comprises a rotor assembly (110) and a stator (112), with the control system (104) adjusting a time integral of rotor speed over time. The control system (104) includes a first control unit (107) and a second control unit (108). The first control unit (107) compares the input order power P₀ to the measured power P₁ to generate a requested angular velocity signal ω₀. The second control unit (108) compares the requested angular velocity signal ω₀ to a measured angular velocity signal ω_r of the rotary transformer to generate a converter drive signal T₀ to a torque control unit (106), thereby controlling the angular positioning (θ_r) of the rotor assembly (110) relative to the stator (112). In various embodiments, the torque control unit (106) is integrated in the rotor assembly (110) and stator (112) of the rotary transformer (102).

Claims

1. An electrical interconnection system comprising:

a rotary transformer for coupling to a first electrical system and to a second electrical system, the rotary transformer comprising;

a rotor connected to the first electrical system;

a stator connected to the second electrical system;

a controller which adjusts an angular position of the rotary transformer, the controller comprising;

a first control unit which compares an input order power signal P₀ to a measured power signal P₁ being transferred between the first electrical system and the second electrical system to generate a requested angular velocity signal ω

₀;

a second control unit which compares the requested angular velocity signal ω

₀ to a measured angular velocity signal ω

_r of the rotary transformer to generate a drive signal T₀.

2. The system of claim 1, wherein the controller adjusts an angular position of the rotary transformer so that a predetermined power is transferred from the first electrical system to the second electrical system.

3. The system of claim 1, wherein the controller has a bandwidth chosen to dampen inherent oscillations in the interconnection system.

4. The system of claim 1, wherein the first electrical system and the second electrical system are a respective first electrical utility company and a second electric utility company.

5. The system of claim 1, wherein the interconnection system further comprises a torque control unit for rotating the rotor.

6. The system of claim 5, wherein the controller controls the torque control unit whereby the rotor is rotated at a variable speed.

7. The system of claim 6, wherein the controller controls the torque control unit whereby the rotor is bi-directionally rotated at a variable speed.

8. A substation for electrically interconnecting a first electrical system and to a second electrical system, the first electrical system and the second electrical system having a differing electrical characteristic, the substation comprising:

a step-down transformer coupled to the first electrical system;

a step-up transformer coupled to the second electrical system;

a rotary transformer coupled to the step-down transformer and to the step-up transformer, the rotary transformer comprising;

a rotor connected to a first of the step-down and step-up transformers;

a stator connected to a second of the step-down and step-up transformers;

a controller which adjusts an angular position of the rotary transformer so that a predetermined power is transferred from the first electrical system to the second electrical system, the controller comprising;

a first control unit which compares an input order power signal P₀ to a measured power signal P₁ being transferred between the first electrical system and the second electrical system to generate a requested angular velocity signal ω

₀;

a second control unit which compares the requested angular velocity signal ω

₀ to a measured angular velocity signal ω

_r of the rotary transformer to generate a drive signal T₀.

9. The system of claim 8, wherein the controller bi-directionally operates the rotary transformer at a variable speed for transferring power from the first electrical system to the second electrical system.

10. The system of claim 8, wherein the rotary transformer comprises:

a rotor connected to a first of the step-down and step-up transformers;

a stator connected to a second of the step-down and step-up transformers;

and wherein the interconnection system further comprises an torque control unit for rotating the rotor.

11. The system of claim 10, wherein the controller controls the torque control unit whereby the rotor is rotated at a variable speed.

12. The system of claim 8, wherein the controller has a bandwidth chosen to dampen inherent oscillations in the interconnection system.

13. An electrical interconnection system comprising:

a rotary transformer for coupling to a first electrical system and to a second electrical system, the rotary transformer comprising;

a rotor connected to the first electrical system;

a stator connected to the second electrical system;

a closed loop angular positioning control system which operates the rotary transformer for transferring power from the first electrical system to the second electrical system in response to a comparison between an input order power signal P₀ and a measured power signal P₁ being transferred between the first electrical system and the second electrical system.

14. A method of interconnecting two electrical systems, the method comprising:

coupling a rotor of a rotary transformer to a first electrical system and a stator of the rotary transformer to a second electrical system;

comparing an input order power signal P₀ and a measured power signal P₁ being transferred between the first electrical system and the second electrical system to generate a requested angular velocity signal ω

₀; and

adjusting an angular position of the rotary transformer so that a predetermined power is transferred from the first electrical system to the second electrical system, the adjusting being performed by a closed loop angular positioning control system which operates the rotary transformer for transferring power from the first electrical system to the second electrical system.

15. The method of claim 14, further comprising:

comparing the requested angular velocity signal ω

₀ to a measured angular velocity signal ω

_r of the rotary transformer to generate a drive signal T₀.