Voltage controller

• US 4,630,220 A
• Filed: 03/06/1984
• Issued: 12/16/1986
• Est. Priority Date: 03/06/1984
• Status: Expired due to Fees

• Current Assignee: Southern California Edison Company (Edison International)
• Original Assignee: Southern California Edison Company (Edison International)
• Inventors: Peckinpaugh, Roger I.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Teska, Kevin J.
• Application Number:
  US06/586,852
• Time in Patent Office: 1,015 Days
• Field of Search: 364/153, 364/483, 364/492, 364/493, 364/571, 361/52, 361/53, 323/255, 323/256, 323/257, 323/263, 322/21, 322/32, 322/24, 322/25, 322/28, 340/646, 340/661, 307/31, 307/33, 318/624
• US Class Current: 700/298
• CPC Class Codes: G05F 1/153 controlled by discharge tubes or semiconductor devices

Abstract

A control device for regulating the output voltage of a voltage regulator wherein the output from that regulator would normally be variable includes inputting that voltage to the control device. There are two overlapping bands which define an effective bandwidth between the upper limit of the lower band and lower limit of the upper band. The output of the device provides a signal responsively regulated in the effective bandwidth such that the output from the regulator can be similarly regulated. In power generation systems a narrow bandwidth can be effectively maintained to permit narrow variations of voltage. A micro-processor facilitates changing the regulated levels for the control device such that the output from the control device can be selectively and controllably changed as desired.

Claims

1. A control device for creating a controlled output signal comprising means for monitoring an input voltage signal to said device, means for defining at least two bands, said bands being overlapping, means for establishing reference signals to define at least an upper limit and a lower limit respectively of at least two bands, said bands constituting an upper band and a lower band, means for selecting the appropriate band thereby normally restraining the input voltage signal in said effective bandwidth, and means for generating an output signal regulated by said effective bandwidth.

2. A control device as claimed in claim 1, wherein the monitoring means, means for defining the bands, means for selecting the appropriate bands and means for generating said output signal are programmed into a microprocessor.

3. A control device as claimed in claim 1 wherein the output signal effects input voltage changes.

4. A control device as claimed in claim 3, wherein the output signal activates a prime mover, the output of said prime mover being fed back through regulator means to the input voltage signal.

5. A control device as claimed in claim 3, wherein the output signal activates regulator means, and the regulator means feeds the adapted output signal to the input of the control device.

6. A control device as claimed in claim 5 wherein the regulator means further outputs a controlled voltage responsive to the output signal controlled by said bandwidth.

7. A control device as claimed in any one of claims 1 to 4 wherein the size of the effective bandwidth is adjustable.

8. A device for controlling an output voltage signal for operating voltage regulator means, said device comprising:

means for receiving an input voltage signal from the output side of the regulator means, said input voltage signal in uncontrolled state tending to rise or decrease varibly;

means to establish reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

means for selecting reference voltages such that the upper limit of the lower band is employed to normally restrain the rise of said input variable voltage signal as an upper limit and the lower limit of the upper band is used to normally restrain the decrease of said input variable voltage signal as a lower limit thereby creating an effective bandwidth between said lower voltage limit of the upper band and said upper voltage level of the lower band;

means for generating an output voltage signal determined by control imparted to the input signal to restrain said input signal in the effective bandwidth, said output voltage signal in turn activates said regulator means to control the output from the regulator in the effective bandwidth.

9. A device of claim 8, wherein the two bands are adjacent to each other, the effective bandwidth being defined between the upper limit of the lower band and the lower limit of the upper band, and effectively a single regulator tap change below the upper limit of the lower band and effectively a single regulator tap change above the lower limit of the upper band.

10. A device as claimed in claim 8, wherein the two bands are spaced apart, such that the effective bandwidth includes the spacing between the bands and effectively a single regulator tap change above the lower limit of the upper band and effectively a single regulator tap change below the level of the upper band.

11. A device for controlling an output voltage signal comprising:

means for receiving an input voltage signal, which input voltage signal in uncontrolled state would tend to rise or decrease variably;

means for establishing reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

means for selecting reference voltages such that the upper limit of the lower band is employed to normally restrain the rise of said input variable voltage signal as an upper limit, and the lower limit of the upper band is used to normally restrain the decrease of said input variable voltage signal as a lower limit, thereby creating an effective bandwidth substantially between said lower voltage limit of the upper band and said upper voltage limit of the lower band;

means for selecting appropriately the upper band or the lower band; and

means for generating an output voltage signal determined by control imparted to the input variable signal to normally restrain said input signal substantially within the effective bandwidth, said output voltage signal in turn controlling the input signal substantially in the effective bandwith.

12. A device as claimed in either claim 11 or 8, including means for changing the input voltage signal, said changes being affected by a micro-processor programmed to generate said desired changes in the input voltage signals to the control device thereby in turn to ensure the output voltage signal responsive to the desired programmed signal.

13. A device as claimed in either claim 11 or claim 8 wherein the reference voltage establishing means includes an operational amplifier connected in input-output follower configuration, a resistor network connected between the amplifier output and input, and outputs between the resistors for obtaining the reference voltages.

14. A device as claimed in claim 13 wherein the resistors are variable thereby to provide variable reference voltages.

15. A device as claimed in either claim 11 or claim 8 wherein there are four reference voltages, said four reference voltages respectively defining two pairs, a first pair for the upper band and a second pair for the lower band.

16. A device as claimed in claim 15 wherein the upper band overlaps with the lower band.

17. A device as claimed in claim 15 including two further reference voltages, each one of those additional reference voltages being related to the bands, the additional reference voltage for the upper band being in the upper band and at a value at least as high as the upper value of the lower band, the additional reference voltage for the lower band being between the limits of the lower band and at least no higher than the lower voltage for the upper band.

18. A device as claimed in claim 15, wherein the reference voltages constituting the upper limit of the upper band and the lower limit of the lower band are normally non-active for output signal control, the input voltage being contained in the effective bandwidth constituted by the other two reference voltages.

19. A device as claimed in claim 15, wherein the upper voltage limit of the upper band and the lower voltage limit of the lower band are effectively operational when the input voltage tends excessively high or excessively low respectively.

20. In a power distribution supply including a power supply to regulator means, an output from said regulator means for feeding a feedpoint in the power distribution system from which feedpoint, power is distributed to consumers, and wherein the voltage at the feedpoint is to be maintained substantially within an effective bandwidth, said power distribution supply comprising:

regulator means between said power supply and a feeder to the feedpoint,

line drop compensator means effectively connected to the feeder between the regulator and the feedpoint for providing an equivalent measure of load change on the feeder and thereby to output a compensated voltage equivalent to a voltage at said feedpoint;

a control device receiving a compensated voltage input signal, said signal normally being variable and tending to rise or decrease as load characteristics change at the feedpoint;

means for reading the compensated input voltage, representative of the voltage at the feedpoint;

means for establishing reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

means for selecting reference voltages, such that the upper limit of the lower band is employed to restrain the rise of said variable compensated voltage signal as an upper limit and the lower of the upper band is used to restrain the decrease of said variable compensated voltage signal as a lower limit, thereby creating an effective bandwidth substantially between said lower voltage limit of the upper band and said upper voltage limit of the lower band;

band selector means for determining the need for a band change from the upper band to the lower band or from the lower band to the upper band thereby to effectively activate either the upper limit of the lower band or the lower limit of the upper band to normally restrain the input voltage in the effective bandwidth;

switch means to selectively change bands for changing the reference voltage for a top changer means; and

relay means for responding to a signal from said tap changer means thereby to raise or lower the tap change control by activating a regulator motor means, and thereby effectively change the status of the regulator and the signal output from the regulator means.

21. A power distribution system as claimed in claim 20 including a micro-processor for programming changes in the control device thereby to ensure that the signal to said control device is desirably varied such that the output signal of the regulator is responsive to the microprocessor programming.

23. A system as claimed in either claim 20 or 22 wherein the effective bandwidth size is related to the size of a step change of the regulator means.

24. A system as claimed in either claim 20 or 22 including timing means for determining a voltage trend and thereby a need for a band change, said band change only be affected after a predetermined time period wherein the compensated voltage signal is beyond the effective bandwidth.

25. A system as claimed in claim 24 including timing means for the tap changer section and the relay means for effecting a position change of the tap changer, such timer means operating cooperatively with the timing means for a band changer controller means.

26. A system as claimed in either claim 20 or 22 wherein the voltage signal being regulated is substantially 120 volts, and the effective bandwidth is maintained at substantially 1 volt.

27. A system as claimed in claim 26 wherein the effective step change of the regulator means is 0.75 volt.

28. A system as claimed in claim 27, wherein the limits of the upper bandwidth are substantially 119.4 volts and 121.4 volts respectively and the limits for the lower bandwidths are substantially 118 volts and 120 volts respectively.

22. In a power distribution supply including a power supply to regulator means, an output from said regulator means for feeding a feedpoint in the power distribution system from which feedpoint, power is distributed to consumers, and wherein the voltage at the feedpoint is to be maintained substantially within an effective bandwidth, said power distribution system comprising:

regulator means between said power supply and a feeder to the feedpoint;

line drop compensator means effectively connected to the feeder between the regulator and the feedpoint for providing an equivalent measure of load change on the feeder and thereby to output a compensated voltage equivalent to a voltage at said feedpoint;

a control device receiving a compensated voltage input signal, said signal normally being variable and tending to rise or decrease as load characteristics change at the feedpoint;

means for transforming said compensated voltage to a representative d.c. signal;

means for generating at least six reference voltages for establishing switching limits;

means for establishing the reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

means for selecting reference voltages, such that the upper limit of the lower band is employed to normally restrain the rise of said d.c. variable voltage signal as an upper limit and the lower limit of the upper band is used to normally restrain the decrease of said d.c. variable voltage signal as a lower limit, thereby creating an effective bandwidth substantially between said lower voltage limit of the upper bandwidth and said upper voltage limit of the lower bandwidth;

band selector means for determining the need for a band change from the upper band to the lower band or from the lower band to the upper band thereby to effectively activate either the upper limit of the lower band or the lower limit of the upper band to normally restrain the input voltage in the effective bandwidth;

switch means to selectively change bands for changing the reference voltage for a tap changer means; and

relay means for responding to a signal from said tap changer means thereby to raise or lower the tap change control by activating a regulator motor means, and thereby effectivly change the status of the regulator and the signal output from the regulator means.

29. A device for controlling an output voltage signal comprising:

means for receiving an input voltage signal normally tending variably to rise or decrease;

means for creating an effective bandwidth between an upper voltage level of a lower band and a lower voltage level of an upper band thereby to form said effective bandwidth, said effective bandwidth being relatively narrower than either the upper band or the lower band;

means for creating a sensing band no less than the effective bandwidth;

means for sensing a voltage excursion beyond the sensing band for predetermined time period; and

means for switching between the upper band and the lower band respectively to thereby maintain the effective bandwidth and thereby cause the output voltage signal to return from the excursion into the sensing band to the effective bandwidth.

30. A control device as claimed in claim 29 wherein during operation in the upper band, the voltage reference for the sensing band is between the upper limit of the upper band and the upper limit of the lower band, and during operation in the lower band the reference voltage for the sensing band is below the lower limit of the upper band and above the lower limit of the lower band.

31. A method of providing a controlled output voltage signal to control a signal which in uncontrolled state would tend to rise or decrease variably comprising:

establishing reference voltages to define an upper voltage limit and a lower voltage limit respectively of at least two bandwidths, said bandwidths constituting an upper bandwidth and a lower bandwidth;

selecting reference voltages such that the upper limit of the lower band is employed to normally restrain the rise of the input variable voltage signal as an upper limit and the lower limit of the upper band is employed to normally restrain the decrease of said input variable voltage signal as a lower limit thereby creating an effective bandwidth between said lower voltage limit of the upper band and said upper voltage limit of the lower band,

operating in the upper band with its lower limit effective;

maintaining such upper band position until the signal passes a further reference threshold voltage beyond the upper limit of the lower band for a predetermined time whereupon a band selector operates to switch the reference voltage to operate on the lower band;

operating in the lower band with its upper limit effective;

maintaining such lower band operation until the signal tends below a further voltage threshold reference below the lower limit of the upper band for a predetermined time; and

returning to the upper band so as to force the input voltage to operate above the upper band lower limit.

32. A method of creating a controlled output signal comprising monitoring an input voltage defining at least two bands which overlap, an effective bandwidth being established between the upper limit of the lower band and the lower limit of the upper band, selecting the appropriate band for normally restraining the input voltage signal in said effective bandwidth, and generating an output signal regulated in said effective bandwidth.

33. A method as claimed in claim 32 wherein the monitoring of the input voltage, selection of the appropriate band, restraint of the input voltage, and generation of the output signal are effected by a programmed microprocessor.

34. A method for controlling an output voltage signal comprising:

receiving an input voltage signal, which input voltage signal in uncontrolled state would tend to rise or decrease variably;

establishing reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

selecting reference voltages such that the upper limit of the lower band is employed to normally restrain the rise of said input variable voltage signal as an upper limit, and the lower limit of the upper bandwidth is used to normally restrain the decrease of said input variable voltage signal as a lower limit, thereby creating an effective bandwidth between said lower voltage limit of the upper band and said upper voltage limit of the lower band;

generating an output voltage signal determined by control imparted to the input variable signal to normally restrain said input signal within the effective bandwidth, said output voltage signal in turn being adapted to control the input signal substantially in the effective bandwidth.

35. A method of controlling an output voltage signal for operating voltage regulator means comprising:

receiving an input voltage signal from the output side of the regulator means, said input voltage signal in uncontrolled state tending to rise or decrease variably;

establishing reference voltages to define at least an upper voltage limit and a lower voltage limit respectively of at least two bands, said bands constituting an upper band and a lower band;

selecting reference voltages such that the upper limit of the lower bandwidth is employed to normally restrain the rise of said input variable voltage signal as an upper limit and the lower limit of the upper band is used to restrain the decrease of said input variable voltage signal as a lower limit thereby creating an effective bandwith between said lower voltage limit of the upper bandwidth and said upper voltage level of the lower band; and

generating said controlled output voltage signal determined by control imparted to the input voltage signal by said regulator means to normally restrain said input voltage signal in the effective bandwidth, said output voltage signal in turn activate said regulator means to control the output from the regulator means normally in the effective bandwidth.