USRE17851E

USRE17851E - Electrical apparatus for automatically controlling peak demands

Info

Publication number: USRE17851E
Authority: US
Publication date: 1930-10-28

Description

Oct. 28, 1930- E. r. MOORE 17,351

ELECTRICAL APPARATUS FOR AUTOMATICALLY CONTROLLING PEAK DEMANDS Original Filed Feb. 14. 1926 s Shets-Shet 1 (g I IIVVEIIV7'0R A 7km lhr ass g g, rw

By flrra IVY8 Oct. 28, 1930. E. T. MOORE Re. 17,851

ELECTRICAL APPARATUS FOR AUTOMATICALLY CONTROLLING PEAK DEMANDS Original Filed Feb, 14, 1920 5 Sheets- Sheet '2 I/vn/vroR (5;): fil rs.

' EM v;

Oct. 28, 1930. 1 E. TQMOORE 17,351

ELECTRICAL APPARATUS FOR AUTOMATICALLY CON'fRULLING PEAK DEMANDS Original Filed Feb. 14. 19 0 '5 Sheets-Sheet :s'

3 K Wliadwtion In no 300 400 J00 600 700 800 900 [m [/00 1200 B00 Load before reduczng .Z'NVENTaR Reieeued Oct. 28, 1930 UNITED STATES EDWARD '1. MOORE, OF SYRACUSE, NEW YORK, ASSIGNOR TO rowan CONTROL OFSYBAOUSE, NEW YORK, A. CORPORATION 01' NEW YORK PATENT OFFICE comm,

ELECTRICAL APPARATUS FOR AUTOMATICALLY CONTROLLING PEAK DEIAN'DS Oritlnal Io. 1, ll08,180, dated July 29, 1924, Serial No. 358,748 filed I'ebruary 14, 1920. Application for reissue filed Kay 25, 1926. Serial No. 111,889.

' duced for a period of time and relates more particularly to apparatus for controlling the power demands of a plant employing electric furnaces where the supply of power may be reduced or interrupted without materially interrupting the output of the furnaces.

It is well known that the operators of central stations or any generating plants object to peak loads for the reason that a greater amount of installed capacity is necessary in order to meet increased power demands existing at that time, and, therefore, the operators of such plants are greatly interested in equalizing its powerdemand. It is particularly true of central stations on account ofthe larger number of its power using customers. In order, therefore, (to encourage its customers to be on the allart to limit their power demands, it is customary for central stations to use a demand charge as well as the regular schedule of rates for energy, this demand similarly charge bein generally based upon the highest average iilowatt demand occurring during any pro-determined interval of, say, 10-15 or minutes, durin some longer interval or period of time, o say, one month.

It is, therefore evident that a consumer whose demand charge increases according as his average kilowatt demand increases, for

an interval, of, say,-15 minutes in one month,

will obviously be desirous of controlling his power demand and it to the lowest value practicable, while the operators of isolated generating plants be desirom of controlling their load demand and reducing fuel consumption.

The main object, therefore, of my present invention is to provide means whereby energy supplied to an electrical installation may be controlled at all times, and, particularly, during periods whenthe deman is high, or, in other words, to provide means for. varying or limiting the average demand made by an electric installation upon the source of power supply by pre-determined value.

' Other advantages and uses relatin to specific parts of the apparatus will be rought out in the following description:

In thedrawings:

Figure 1 is a diagrammatic view of the ensemble of' an apparatus and its connections for carrying out the objects of my invention.

Figures 2 and 3 are diagrammatic detail views of modified types of regulators which may be used in connection with my invention.

Figure 4 is a detailed view of what may be termed a riser bar mechanism.

Figure 5' is a diagram of the curve illus' trating the degree of load reduction for a given load.

. The main source of power supply 1 has potential transformers 2 and current transformers 3 connected as shown, with lead wires 4 extending from the secondary of the instrument transformers 2 and 3 to a watthour meter 5. The power load, which, for purposes of illustration may be composed of several electric furnaces such as 6 and 7, is connected to the source of supply at 8 and 9 by oil circuit breakers 10 and 11.. Any other power load such as electric steel melting furnaces, ferro-alloy electric furnaces, motors, et cetera, ma be connectedonto the power line at 12. Wlien necessary to reduce the line voltage, transformers may'be used as at 13 and 14, whose rimaries I5 and 16 are energized through t e oil circuit breakers 10 and 11. The secondaries 17 and 18 areconnected to the load such as through

electrodes

19, 20, 21,22, 23, 24. The seconda conductors-25 and 26 have current trans ormers 27 and 28 connected in circuit with

secondary leads

29, 30, 31, 32, 33,- 34,

secondary of the ll rent transformers 27 by the leads29, 30, 31, and 32. In Fig. 3, are suitable solenoid coils 64 on panels 40, 41,42, preferably of 5 amperes capacity connected into the circuit of the secondary of the current transformers 28 by the

leads

33, 34, 35, 36.

Ikwill, therefore, be apparent that any fluctuations in load on the furnaces 6 and 7 will cause proportional current changes in the secondaries of the current transformers 27 and 28 and consequently. in the

solenoids

43 and 64. A plunger 44 is within the solenoid 43 and moves 1n an upward and downward direction as the-load on the furnace 6 fluctuates. This plunger 44 is pivoted at 45 to an arm 46 pivoted at 47. The arm 46 has a contact 48 which travels between

contacts

49 and 50. When the load on the furnace 6 becomes higher than a predetermined value, arm 46 will be moved by the actions of the solenoid 43 to cause contact 48 to make contact with contact 49. This action causes anauxiliary contactor (not shown in drawing) to operate to control an'electrode motor which will raise the electrodes 19, 20 and 21 and reduce the load. A lower load on furnace, 6

. will cause solenoid 43 to lowervcont-act 48 of arm 46 so that contact 48 will contact withcontact 50 causing the electrode motor to lower electrodes 19, 20 and 21, which will raise the load on furnace 6. 1

In order to adjust or predetermine the load on furnace 6, a rheostat with resistance 52' and adjusting arm 53 is shunted across the solenoid 43 with permanent resistance 51 in series with rheostat resistance 52. In standard practice arm 53 is directly connected to the solenoid lead at point 54 but for the pur-,

Panels 40, 41 and 42 are similar to each '6 other and to

panels

37, 38 and 39 where like parts are similarly numbered. 'The contact making ammeters on panels 40, 41 and42 are similar to those on

panels

37, 38 and 39, except solenoid 64 differs from solenoid43 in that it is wound up in sections with

taps

65, 66, 67, 68, etc., brought out and terminated on the dial switch 69 with adjusting arm 70. The solenoid coils 64 are connected to the seconda of the current transformers 28 through

eads

33, 34, 35, 36. The action of solenoids 64, plungers 44, arms 46 and contacts 48 on panels 40, 41, 42 will, therefore, be similar to solenoids 43, etc., on

panels

37', 38, 39. In adjusting the. function of solenoids 64 the dial switches 69 are used' on panels 40, 41, 42, whereas on

panels

37, 38, 39,

solenoids 43 are adjusted by the rheostat 52.

For the purposes of this invention a special resistance 71 of a value of approximately 9 ohms is connected between

points

72 and 73. Normally this special resistance 71 is'shunted across the points64 and for the relay 74 has its contact 75 and 76 closed, as the solenoid 77 is not energized. When the demand reaches the predetermined value, the solenoid 77 will be energized, plunger 78 raised, and contacts 75 and 76 opened, causing the adjustment of the current and ampere turns in solenoid 64 to be changed, permitting plunger 44 to rise, and contact 48 to touch contact 50, thus raising electrodes of the furnace 7 and reducing the loadon the supply mains 1. 4

The

special resistances

58 and 71 will not always be of the same value in ohms since one feature of this invention is to so proportion this resistance that the percentage the load is reduced automatically when the predetermined demand has been'reached will be di- I rectly proportional to the value of the load 1250 kw., the load will automatically be reduced 300 kw., to 950 kw., at 1000 kw., reduced 210 kw., to 790 kw., at 500 kw. reduced 75 p kw. to1425 kw. This gradation in load can be changed at any time by changing thevalue of the

special resistances

58 and 71, although for most purposes the resistance should be adjusted for a value to produce reductions as indicated in Figure 5. These

resistances

58 and 71 may be arranged with taps and so connected that .the load value of reduction may be changedinstantly at any time either manually or automatically. There will also be instances where the load reduction should be made .a certain definite percentage of the existing load irrespective as to whether the load is great or small. Also, there will be instances where the loadreduction should be a certain definite kw. value irrespective of the size of the load. It is also obvious that a certain combination of these methods of load reduction may he used to advantage for the purpose of this invent-ion. j The watthour meter 5 may be any of the commercial polyphase meters on the market. or several single phase meters but for our purpose herewith a polyphase meter is used having a rotating shaft 79 with disc 80. The shaft 79 has a worm gear 81 which meshes with a spur gear wheel 82 and through the shaft 79, the insulated toothed wheel 83 is rotated. This toothed wheel 83, may have one, three, five or a suitable number of teeth depending upon the meter constant. The toothed wheel 83 causes the contacts 84 and 85 to be alternately closed momentarily thus energizing the circuit 86 and the electromagnet 87. For every revolution of the meter disc 80, therefore the electromagnet 87 will be energized two, six orten times or twice the number of times that the toothed ,wheel 83 has teeth. When the electromagnet 87 is ener-' gized, the arm 88 which is pivoted at 89 and with a tooth 91 of meter contact riser bar 92.

when the five minute circuit 100 and ma The meter contact riser bar 92 has a contact 96 and is connected into the circuit 97 through the flexible lead 98.

The contact making clock 99 is arranged to give out momentar electric impulses every five minutes over t e circuit 100 and ever fifteen minutes over the circuit 101, although these periods of time may be adjusted to meet an desired condition.

, hen the five minute contact is made over circuit 100 the magnet 102 is momentarily energized causing plunger 103 and finger 104 to be raised. Since finger 104 is pivoted at 105 and normally held-out of contact with teeth 107 by the stop 106, it .will be seen that 'et 102 is momentarily energized by the cloc 99 the lunger 103 and finger 104 will pull the clociz contact riser bar upward a distance 118 ual to the travel of the plunger 103. The p unger 103 however, will return immediately to its downward position by the action of gravity as soon as the electric impulse ceases from clock 99 and in this downward position the finger 104 is held out of mesh with the teeth 107 by the stop 106. As soon as plunger 103 has raised a trifle the finger 104 is raised 01! the stop 106 so that finger 104 will mesh with teeth 107 and pull the clock contact riser. bar 108 upward. This riser bar 108 has a contact 109 and flexible lead 110. When the magnet 102 releases the pl'mger 103 and fin er 104, the finger 104 will slide past the teet 107 of'the clock contact riser bar 108 because the downward friction of finger 104 against the teeth overcomes the tension of its

drawi teeth

91 and 113 of riser bars 92 and 108 reactuating spring. Clock contact riser bar-108 will remain in its upward position as drawn by the magnet 102 since arm 111 ivoted at 112 is held against the teeth 13 o the riser bar-108 by action of the spri g 114.

When the fifteen-minute ntact is made by theclock 99. over circuit 1 1, the

magnets

115 and 116 are momentarily energized, thus arms 93 and 111 away from the spectiveliyl, causing riserbars 92 and 108 to drop to t eir downward position at 117. The

the circuit 121.

It will, therefore, be apparent that as the meter disc 80 of meter 5 rotates faster due to' an increasing use of energy in the circuit 1 the meter contacts 84 and 85 will be closed a greater number of times in a given interval, thus causing the magnet 87 to pull the meter contact riser bar 92 upward in equal successive stages a greater-number of times. Then the meter contact riser bar 92 and clock contact riser bar 108 are in their downward position at 117 there is a certain predetermined distance between contacts 96 and 109 of the riser bars 92 and 108. This distance 118 is variable by moving thecontacts 96 and 109 and is proportional to the maximum demand which has been determined as the energy demand not to be exceeded. Every five minutes beginning at five minutes after the hour the magnet 102 is energized causing contact 109 to be raised to the position 119. If the energy consumed has not been sufficient to cause the disc 80 of meter 5 to rotate to cause the riser bar 92 to rise enough to allow contact 96 to touch contact 109, no action will result, and'at ten minutes after the hour, the riser bar 108 will be pulled into position 120. If the energy consumption has not reached the predetermined amount at the end of fifteen minutes, the contacts 96 and 109 will not touch and no action results. At the end of the fifteen minute period the

magnets

115 and 116 will cause the riser bars 92 and 108 to drop to their downward position at 117 This process will be repeated every quarter of an hour when the contact makin clock 99 is arranged accordingly to suit a fi en minute demand period. It will be understood; however, that any demand period could be selected and the apparatus adapted accordof solenoid "64 depending on the position of arm 70 on

taps

65, 66, 67, 68, etc., thus-weakening the effective pulling power of

solenoids

43 and 64, causing plungers 44 to rise and contacts 48 to touch contacts 50, thus operating the electrode motor mechanism to raise the electrodes and thereby reduce the load.

special resistance 71 across one or more coils It should be noted that contact 96 is raised 1 one tooth at a time at a rate dependin solely upon the speed'of the meter disc 80. ts rate 0 travel is, therefore, not uniform. Contact 96 on the other hand is normally a distance 118 below contact 109, equivalent to a five minute period or one third of the demand rate. At the end of thefirst five minutes, contact 109 is raised a distance equal to 118 to position 119. At the end of ten minutes, contact 109 will be raised a distance equal to 118 to position 120, which is equivalent to three five minute periods or the total demand period in question. The contact 109,

' has been described, one type on panels 37,

38, 39, the other type on panels 40, 41,42. It will be understood, however, that one or more of each or both of these types of regulators can be used in an illustration and it will occur to those skilled in the art that other types of regulators including the well known Thury regulator may be adapted for this invention. In' adapting the Thury sys-' tem of furnace control to this invention the special resistance 58 of suitable value is connected in series with the-Thury regulator rheostat much the same as the special resistance 58 isconnected in series with rheostat 52. The Thury regulator rheostat is shunted across the terminals of the actuating solenoid, and this actuating solenoid is connected to the secondary ofcurrent transformers such as at 27 and 28, the Thury solenoid corresponding to solenoid 43 and having similar functions. 1

The meter contact riser bar 92 and clock contact riser bar 108 for the purposes of this invention moves in an upward and downward direction-but it will be understood that we do not limit ourselves to this upward and downward motion since a suitable contact 96 could be arranged on a horizontal bar or a wheel and contact 109 arranged on another parallel horizontal bar or adjacent wheel having a common axis, in such manner that contact 109 would normally be in advance of contact 96. In the event'the revolution of the wheel having contact 96 was'greater than the revolution of wheel having-contact 109, then contact 96 under such conditions would overtake and make contact with contact 109, causing similar action in circuit 97 as described hereinbefore. The contacts '96 and 109 may, therefore, beproperly actuated in a rotary, horizontal or vertical direction al though we have found the vertical motion to be much superior to the other.

While the above specification has referred to electric furnace regulators, it has been done merely for descriptive purposes for ob- "viously'its use can be adapted to and will be found advantageous for other types of regulators or for use without regulators. V

a I have described my invention by drawings and by describing the various functions of the component parts, but it will be understood that my invention inay be used in many other forms. I do not, therefore, wish to be restricted to the exact details of construction as disclosed herein, which have been shown by way of example for the purpose of setting forth my invention. The appended claims are not restricted to the precise constructions disclosed, but are intended to cover all changes and modifications within the spirit and scope of the invention. Furthermore, the movement of the riser bars 92 and 108 may be recorded by suitable markers actuated thereby. upon a chronometer actuated rotary dial or record sheet thereon to graphically show the conditions of load in the working circuit for any of the predetermined intervals of time, as for example, during each 15 minute period, the. use of such a device being contemplated in connection with the riser bars or equivalent mechanism.

I claim asmy invention the following 1. The combination with an electric working circuit including therein an electric meter, of automatic means f r controlling the peak demands in said ci cuit, comprising normally spaced cooperative contacts mov able one in relation to the other, electrically operated means controlled by said meter for gradually moving one of the contacts toward the other at. a rate of speed proportionate to the speed ofthe meter and electrically operated means controlled by said contacts for causing a reducing of the powerbdemands in said circuit in case the contacts should be closed during a predetermined interval of time.

2. The combination with an electric working circuit including therein an electric meter, of means for automatically contro1- ling peak demands insaid circuit, comprising normally spaced cooperative contacts movable one in relation to the other, electrically operated means controlled by said meter for moving one of said contacts step by step toward the other contact, electrically operated means controlled by said contacts for reducing said demands in case the contacts shouldbe closed during a predetermined interval of time, means for holding the movable contact in its adjusted position and chronometer controlled electrically opermeans from its holding, position at the end of said interval of time.

a' controlling circuit, an electromagnet,

means actuated by the meter for producing impulses in the electro-magnet at a rate of speed proportionate to that of the meter, means actuated by said electro-magnet at each impulse for adjusting one of the contacts toward the other, means for holding said contact in its adjusted position, an elec- 6 ing said demand in case said contacts should be closed during one of said intervals of time.

4. The combination with an electric working circuit including therein an electric meter, normally separated cooperative contacts of a controlllng circuit movable each in relation to the other, an electro-magnet, means actuated by the meter for producing current impulses in the electro-magnet at a rate of speed proportionate to that of the meter, means actuated by said electro-magnet at each impulse for adjusting one of the contacts step by step toward the other contact, means for holding said contact in its adjusted position, chronometer controlled electrically operated means for adjusting the other contact in the direction of the first named contact at regular pre-determined intervals of time, separate devices for holding said contacts in their adjusted position, chronometer controlled electrically operated meansfor tripping said devices at the end of a redetermined interval of time, and electrically operated means controlled by said controlling circuit for reducing said demands in case said contactsshould be closed during any one of said intervals of time.

5. Thecombination with an electric working circuit, including therein an electric meter, normally spaced cooperative contacts of a controlling circuit, movable each in relation to the other, an electro-magnet, meter actuated means for producing current impulses in said electro-magnet at a rate of speed proportionate to that of the meter, means actuated by said electro-magnet at each impulse for adjusting one of the contacts step by step in one directlon, chronometer controlled electrically operated means for adjustin the other contact step by step in the same irection as that of the first-named contact and at re-determined intervals of time, devices for olding said contacts in their adjusted position, chronometer controlled electrically operated means for tripping said devices at the end of a pre-determined interval of time, a solenoid connected in said controlling circuit and electrically operated means controlled by said solenoid for reducing said demands in case the "contacts are closed during any one of said intervals of time.

6. A maximum power demand controller for electrical power installations-comprising an energy meter in the power circuit, a pair of nonexible bars movable in the same general direction and provided with cooperative contact members normally s aced apart, in the direction of movement f8 mal positions, mder-controlled electrically om their noroperated means for moving one of said bars a distance depending upon the speed of the meter for a given period of time to cause its contact member to approach that of the other bar, whereby the contact members will be brought into contact in case the speed of the meter exceeds a pre-determined degree during said given period of time and, electrically operated means brought into action by the closing of said contact members for reducing the power demand in'the power circuit, means for holding the adjusted bar in its adjusted position and chronometer controlled electrically operated means for releasing said holding means at the end of a pre-determined interval of time not less than the first named period.

7. A maximum power demand controller for electrical power installations comprising an energy meter in the power circuit, a pair of non-flexible bars movable in the same general direction and provided with cooperative contact members normally spaced apart in the direction of movement from their normal positions, meter-controlled electrically operated means for moving one of said bars a distance depending upon the speed of the meter for a given period of time to cause its contact member to approach that ofthe other bar, whereby the contact members will be brought into contact in casedthe speed of the meter exceeds a predetermined degree.

during said given period of time and, electrically operated means brought into action by the closing of said contact members for reducing the power demand in the power circuit, the normal distance between the contact members being proportional to the pre-determined maximum energy demand for said given period. a

8. A maximum power demand controller for electrical power installations comprising an energy meter in the power circuit, a pair of non-flexible bars movable in the same general direction and provided with cooperative contact members normally spaced apart in the direction of movement from their normal positions, meter-controlled electrically operated means for moving one of said bars a distance depending upon the speed of the meter for 'a- 'ven period of time to cause its contact mem er to approach that of the other bar, whereby the'contact members willbe brought into contact in case the s eed of the meter exceedsa pre-determined egree dur- .ing said given period of time and, electrically operated means brought into action by the c o sing of said contact members for reducingv for electrical power installations comprising an ener meter in the power circuit, a pair of nonexible bars movable in the same general direction and provided with cooperative contact members normally spaced apart in the direction of movement from their normal positions, meter-controlled electrically operated means for moving one of said bars a distance depending upon the speed of the meter for a given period of time to cause its contact member to approach that of the other bar, whereby the contact members will be brought into contact in case the speed of the meter exceeds a pre-determined degree during said givenperiod of time, and electrically operated means brought into action by the closing of said contact members for reducing the power demand in the power circuit, chronometer controlled electrically o erated means for moving said other bar step y step at the end of successive pre-determined intervals of time to cause a similar step by step movement of its contact member away from the first named contact member.

10. A maximum power demand controller for electrical power installations comprising an energy meter in the power circuit, a pair of non-flexible bars movable in the same general direction and provided with cooperative contact members normally spaced apart in the direction of movement from their normal positions, meter-controlled electrically operated means for moving one of said bars a distance de endingupon the speed of the meter for a given period of time to cause its contactmember to approach that of the other bar, whereby the contact members will be brought into contact in case the speed of the meter exceeds a pre-determined degree ,during said given period of time, and'electrically operated; means brought into action by the closing of said contact members for reducing the power demand in the power circuit, means for holding said other barin its different positions of adjustment, and chronometer controlled electrically operated means for releasing said holding means at the end of the last of the successive movements of the bar.

11; A maximum power demand controller for electric furnace mstallations, comprising a, current element responslve to varying loads Q on the furnace, means including the electric furnace for efiecting a reduction in the power demand on said furnace, and means responsive to the action of the current element for effecting the operation of the first-named means when the current energy in the furnace exceeds a predetermined amount during a predetermined intervalof time.

12. -A maximum power d mand controller for electrical power installations, including an electric furnace and'electrodes movable into and out of contact withthe molten metal, and means for operating the electrodes, in

combination with means including an'electrical resistance for controlling the electrodeoperating means, an energy meter in the power circuit, and means responsive to the action of the meter for cutting in said re sistance when the power demand in the power circuit exceeds a. predetermined amount during a predetermined interval of time.

In witness whereof I have hereunto set my hand this 17th day of May, 1926.

- EDWARD T, MOORE.