Synchronous motor KVAR regulation system

• US 4,064,419 A
• Filed: 10/08/1976
• Issued: 12/20/1977
• Est. Priority Date: 10/08/1976
• Status: Expired due to Term

• Current Assignee: AEG Westinghouse Industrial Automation Corporation
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Peterson, Robert S.
• Primary Examiner(s): Hohauser, Herman J.
• Application Number:
  US05/730,889
• Time in Patent Office: 438 Days
• Field of Search: 318/179, 318/174, 318/178, 318/438, 323/117, 323/102, 323/108, 323/119
• US Class Current: 323/201
• CPC Class Codes: H02J 3/1885 using rotating means, e.g. synchronous generators
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y10S 174/16 in a motive power system, e.g. electric motor control system
• CPC Class Codes: Y10S 174/17 in an electric power conversion, regulation, or protection system

Abstract

This disclosure relates to a synchronous motor KVAR regulation system which utilizes a synchronous motor connected to a power distributor line to generate corrective (capacitive) KVARS to automatically follow and compensate for KVARS being generated by the other loads on the distribution line. The system takes into consideration the thermal capacity (motor rated current) of the synchronous motor so that the KVAR regulation system is not permitted to overexcite the synchronous motor for long periods of time. The KVAR regulation system also programs a minimum motor field current with respect to the motor load so as to insure that the synchronous motor will not pull out of synchronism during peak loads.

Claims

1. A system for regulating the inductive KVARS demanded by a power distribution line comprising:

a. a synchronous motor connected to the power distribution line;

b. a field current control loop connected to the field winding of said synchronous motor;

c. means coupled to said power distribution line for deriving a signal which is a function of the inductive KVARS demanded by the other loads on said power distribution line;

d. KVAR controller means for receiving said derivative inductive KVAR signal and for delivering a compensating KVAR signal to said field current control loop to overexcite said synchronous motor to deliver capacitive KVARS to said power distribution line;

e. field current thermal control means coupled to said field current control loop, for receiving a maximum field current signal and for delivering a limit signal to said KVAR controller to inhibit the output signal for said KVAR controller when the average field current exceeds said maximum field current signal; and

f. torque compensator means coupled to the armature of said synchronous motor and connected to deliver a minimum field current to said field current control loop to insure that the synchronous motor will remain in synchronism during normal peak loads, all in the order of priority;

first, synchronism control, next, field thermal control, and finally, compensating KVAR control.

2. A KVAR regulating system according to claim 1 wherein said inductive driving means comprises bus KVAR transducer means, motor KVAR transducer means summation means, said bus KVAR transducer means being connected to said power distributor line to measure the total KVARS, said motor KVAR transducer means being connected to said motor to measure the motor KVARS, summation means algebraically adding said motor and bus KVARS to provide said derivative inductive KVARS signal.