US1744210A - Sectionalizing switch - Google Patents

Description

Jan. 21, 1,930.

C. A. BUTCHER SECTIONALIZING SWITCH Filed Aug. 12. 1922 i a2 1 l I 142 I WITNESSES: INVENTOR Chavles A.Bu1',che\-. v

ATTORNEY Patented Jan. 21, 1930 UNITED STATES PATENT Q-FFEE CHARLES A. BUTCHER, OF EAST PITTSBURGH, I'ENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A COREORATION OF EENN- SYLVANIA SECIIONALIZING SWITCH Application filed August 12, 1922. Serial No. 581,319.

My invention relates to automatically reclosing circuit-controlling devices and is particularly applicable to that type of device known as a sectionalizing switch.

One object of my invention is to provide a sectionalizing switch for connecting two sections of a system that shall connect such sections only so long as current traverses the switch in a predetermined direction.

Another object of my invention is to provide an automatically operating sectionalizing switch that shall connect a system having a large source of power to a system having a small source of power, when the smaller system is loaded to a predetermined degree, to take care of the peak loads, and that shall disconnect the two circuits when the load decreases and the smaller system tends to transmit energy into the larger system.

Another object of my invention is to provide a system, of the above-indicated character, in which the sectionalizing switch, in addition to controlling the direction of current between the two systems, shall be operative to connect the larger system to the smaller only when the smaller system is free of shortcircuit conditions and the resistance of the load connected thereto exceeds a predetermined value.

In practicing my invention, I provide means that are responsive to the respective voltages of the two sections or systems and co-operating means that is responsive both to the potential difference or gradient between the two systems and the direction of such gradient to control the connecting means that joins the two sections or systems.

In order to preclude the operation of the connecting means to join the two sections or systems while a short-circuit condition exists on the smaller section or system, I provide means constituting a measuring circuit to also control the connecting means.

I also provide a reverse current or energy device that operates to disconnect the two systems when the smaller tends to transmit current to the larger system or when the direction of current between the two sections reverses.

Figure 1 of the accompanying drawing is a diagrammatic view of an electrical system including the circuit arrangement embodying my invention.

Fig. 2 is a schematic View of the circuit relations between various resistors of the system, illustrating the VVheatstone bridge arrangement composed thereby.

Fig. 3 is a schematic view of the resistors and the relay constituting the measuring means in a modified arrangement.

Referring to Fig. 1, two sections or systems 1 and 2, respectively, are to be connected by a circuit-controlling device, such as a sectionalizing switch 3, to permit current to be transmitted from section 1 to section 2. It is desired to efiect such connection only when the voltage of section 1 is normal and the voltage of section 2 decreases to a value that is at least some predetermined value less than the voltage of section 1, such, for example, as a diiierence of 100 volts. If section 1 is in proper energy delivering condition and section 2 is clear of short-circuits and the resistance of the connected load is more than a predetermined value, the sectionalizing switch will be closed.

In order to ascertain when the voltage of section 2 decreases to or below a predetermined value, a voltage relay &' is employed that closes its switch when the voltage of circuit 2 decreases to or below such value. A similar voltage-responsive relay 5 is employed to determine whether or not the voltage of section 1 is normal, or sufficiently near normal, in its value, to permit the connection of the additional load of circuit 2 to section 1. The relay 5 is adjusted to close its switch ata predetermined voltage of section 1 at or above which it is permissible to connect the two sections.

In order to determine whether the potential gradient established by the potential difference between section 1 or section 2 is in the proper direction when the predetermined potential difference between the two sections exists, a polarity relay 6, similar in operation to polarized telegraph relays, is connected between the sections 1 and 2 across the terminals of the sectionalizing switch 3. The polarity relay 6 closes its switch when the potential difference between the sections attains a predetermined value and is in the proper direction.

Assuming the proper condition for the operation of the three relays 4, 5 and 6, namely, that the voltage of section 2 decreases to a. predetermined value, the voltage of section 1 is normal and the potential gradient between the sections is in a predetermined direction andof a predetermined value, the voltage relay 5 will be energized through the switches 4 and 6 and an interlock switch 7 controlled by the sectionalizing switch 3. The voltage" relay 5 thereupon closes its switch 8.

In order that section 1 may not be connected to section 2 immediately upon the indica tion of low voltage conditions on section 2 that may be caused by a short-ci'rcuit'on that section, a resistancesmeasuri'ng circuit is set up as a final step tocontrol the closing of the 'sectionalizing switch. Such resistance-measuring circuit comprises two. resistors 9 and 10,. respectively, connected in series between the sections 1 and 2, and an operating coil of a relay 11, that is connected in series with a resistor 12, between the junction of the resistors 9 and 10 and a. common return conductor 130i the system.

It will. be observed that, in the measuring circuit set up,,the operating coils of the relay 11 and the resistor 12 are connected in shunt relation to the resistor 10 and a connected load 14 on the circuit 2. As the resistance of the connected load varies, the potential difference across the resistor 10 and. the con? nected load; 14 in series, varies, and corre-- spondingly the potential ditlerence available to energize the winding ofthe, relay 11 varies.

The relay 11 thus serves, in. eliect, to measure the resistance of the. connected load 14 by the potential difi'erence across the resistor 10 and the connected load. 1 1. The operation is illustrated by the schematic arrangement shown in Fig. 3. i

The sensitivity of the control relay 11 may be varied by shifting the point of connection of the relay 11 between the resistors 9 and 10. By employing a resistor 9 having; a re-. sistance exceeding that of the resistor 10, the sensitivity of the relay device 11 may be. increased in the arrangementthat is illustrated in Fig. 3. 7

If the resistance of the circuit including. the resistor 10 and. the connected load 1d,

. equals or exceeds a predetermined value, the

relay 11 will be sufficiently energized to close its switch. A circuit is completed thereby to energize the operating coil of. a relay 15 which thereupon closes its switches 16. and 17,. respectively. The switch 16' is connected in parallel relation. to the switch of the relay 11 and serves to maintain aiholding circuit for the relay 15.. Iahe. switch 17,. when closed, completes the circuit of. theoperating coilot the sectionalizing, switch 3. which thereupon closes the switch to connect the sections 1 and 2.

If the load on section 2 should now decrease to such value that the voltage of that circuit becomes normal and tends to transmit current back into section 1,a reverse current relay 18 closes its switch 19 to short-circuit and deenergize the winding of the relay 15. The switches 16 and 17 are thereupon opened and the" sectionalizing switch 3 is opened to disconnect the two sections 1 and '2. The reverse current relay 18 has a voltage winding 20 connected across the section 1 and a winding 21 connected toa portion of the section conductor which serves as a current shunt.

It will be. noted that, with the addition of the resistor 22,.shown in broken line in Fig. 1, the arrangement composed by the resistors 9, 10, 12 and 22 and the relay 11 constitutes a Wheatstone bridge of which the resistor 10 and the connected load 14. constitute one arm. The arrangement is illustrated in Fig. 2. The relay 11 may be adjusted tooperate in response to any predetermined potential difference between the points to which it is connected.

It will. be noted that, by means of the system which I have here illustrated as embodying my invention, the two sections will be automatically connected when the voltage of the current-supplying section is normal and the voltage of the current-receiving section is at, or below, a predetermined value below normal, and the potential difference and the potential gradient between the two sections are of a predetermined, value and in a pie determined direction. ing switch is maintained. closed only until the conditions-in the. current-receiving section become normal and the direction of current between the sections is reversed. By means of the resistance-1neasuring arrangements, the immediate connection of the two sections is prevented if a short-circuit obtains on the current-receiving section.

Although I have specified theconnecting of two sections, the switching apparatus which I have here illustrated is applicable to two systems, such as a large city system and a small interurban system.

Apparatus of different types may be employed and various changes maybe made in the arrangement thereof without departing from thespirit and scope of my invention, asset forth in the appended claims.

I claim as my invention:

1. In an electrical distribution system, the combination with two circuit sections, ofan automatically reclosing sectionalizing circuit breaker for connecting said sections, means for closing said circuit breaker, said closing means being. controlled by means responsive to'normal potential on one of said sections, means responsive to the reslstance ot the other Also, the sectionalizsection, and means responsive to the diiference in the potentials of said sections.

2. In an electrical distribution system, the combination with two adjacent circuit sections,of a sectionalizingswitch for connecting said sections, a closing coil therefor, a relay for connecting said coil to a source of current, said relay being controlled by means responsive to an energy-delivering condition of a predetermined one'of said sections relative to the other section, and means for measuring the resistance of the other section.

3. I11 an electrical distribution system, the combination with two adjacent circuit sections, of a circuit breaker for connecting said sections, an actuating coil for said breaker, a relay for controlling said coil, said relay being controlled by means responsive to an energy-deliverying condition of a predetermined one of said sections relative to the other section, and means responsive to the resistance of the other section, and means responsive to current flow to said first-mentioned section from the other section for opening said circuit breaker.

4. In a distribution system, the combination with two adjacent circuit sections of a circuit breaker for connecting said sections, means for controlling the operation of said circuit breaker including means responsive to a voltage on one of said sections in excess of that on the other section, means responsive to the resistance of the latter, and independent means responsive to the voltages of said sections.

5. In a distribution system, the combination with two adjacent circuit sections, of a circuit breaker for connecting said sections, and automatic means for controlling said circuit breaker including means responsive to the direction of the potential gradient between said sections, means responsive to the resistance of one of said sections, and means responsive to the voltages of said sections.

6. In an electrical system, the combination with two circuit sections and connecting means therefor having an operating coil, of means for controlling the energization of the operating coil including resistance means connected between the two sections, a relay responsive to the potential drop across the resistance means, a relay responsive to the di rection of the potential gradient between said circuits, and means responsive to the respective voltages of each circuit section.

7 In a distribution system, two circuit sections adapted to be connected by a circuit breaker, a closing coil for said breaker and means for controlling said coil including relays responsive to the voltages of said sections, to the direction of the voltage gradient therebetween and means responsive to the resistance of one of said sections.

8. In an electrical system, the combination with two adjacent circuit sections, of switching apparatus for connecting the two sections, an operating coil therefor, and means for controlling the operating coil including means responsive to the direction of the potential difference between the two sections, and a Wheatstone bridge for measuring the resistance of the load connected to one of the sections.

9. In an electrical system, the combination with two adjacent circuit sections, of means for connecting the two sections, an operating coil therefor, an auxiliary switch that closes when the connecting means is in open position, a resistor between the circuit sections to limit the transfer of current therebetween when the connecting means is in open position, a relay device connected between predetermined points of the resistor to be energized by the potential drop therebetween, and a second relay adapted to be connected to one section and controlled by the auxiliary switch of the connecting means, and a relay responsive to the direction of the potential gradient between said sections, said relays co-operating to control the energization of the operating coil of the connecting means.

10. In an electrical system, the combination with two adjacent circuit sections, of switching apparatus for connecting the two sections comprising an electromagnetic contactor provided with an operating coil, selfresetting means responsive to predetermined current conditions in the sections for rendering the operating coil ineffective, a resistor between the sections to limit the transfer of current after the contactor opens, means responsive to the voltages of said sections and the voltage gradient between the sections, and a relay adapted thereby to be connected be tween predetermined points of said resistor, to control said operating coil in accordance with the resistance of one of said sections.

In testimony whereof, I have hereunto subscribed my name this 5th day of August, 1922.

CHARLES A. BUTCHER.

Images