Patent Grant
10784063
Not applicable.
Not applicable.
Not applicable.
The present invention relates to vacuum circuit breakers. More particularly, the present invention relates to circuit breakers having a mechanically interlocked grounding switch. Additionally, the present invention relates to circuit breakers with a mechanically-interlocked grounding switch for use in association with wind and solar farm collection circuits.
Wind farms are becoming increasing popular for the generation of electricity. In a wind farm, there are a large number of wind energy generators installed in locations of the country where wind is consistent and substantial. Typically, the wind energy generators will include an array of blades that are coupled to a shaft. The rotation of the shaft caused by the rotation of the blades will produce electrical energy. Electrical lines will connect with the energy generator so as to deliver the energy from a particular wind energy generator to a collection bus. The electrical energy from the various wind energy generators in the wind farm can collectively pass energy to a substation.
Typically, these wind turbines can each produce between 500 kW and 3500 kW of power. The outputs of generators in the wind farm are often grouped into several electrical collection circuits. Transformers are used so as to tie the wind turbine output to the 34.5 kV collection circuits. The transformers serve to step up the output voltage of the wind energy generators to a medium voltage, usually 34.5 kilovolts. The various wind turbines in a wind farm are usually paralleled into collection circuits that can deliver 15 to 30 megawatts of power. In view of the voltage which has been stepped up to the 34.5 kilovolts, each collection circuit will require a circuit breaker rated at a minimum 34.5 kilovolts capacity. The energy will pass through the circuit breaker to the 34.5 kV bus of a substation. The 34.5 kV substation bus will go into one or more main step-up transformers and then tie into a high voltage utility line. As such, a need has developed so as to provide a circuit breaker that can tie collection circuits into the 34.5 kV substation bus. Such a circuit breaker should be of low cost, weatherproof, and able to effectively break the current in the event of a problem condition or fault.
Typically, with circuit breakers, the circuit to the substation can be broken upon the application of a manual force to a button or lever of the circuit breaker or by an automatic relay which opens the circuit. Typically, the current is measured to the substation. If any relay senses a problem, then a signal is transmitted to the circuit breaker so as to open the breaker. Typically, the relays will be maintained within the substation. The opening of the circuit breaker will prevent the energy from being transmitted to the substation. Sometimes, the circuit breaker is open so as to allow users to work on the wind farm system, on the circuit breaker, or on the substation. Typically, the relays will operate if the sensors sense a voltage drop.
The interruption of electrical power circuits has always been an essential function, especially in cases of overloads or short circuits, when immediate interruption of the current flow becomes necessary as a protective measure. In earliest times, circuits could be broken only by separation of contacts in air followed by drawing the resulting electric arc out to such a length that it can no longer be maintained. This means of interruption soon became inadequate and special devices, termed “circuit breakers”, were developed. The basic problem is to control and quench the high power arc. This necessarily occurs at the separating contacts of a breaker when opening high current circuits. Since arcs generate a great deal of heat energy which is often destructive to the breaker's contacts, it is necessary to limit the duration of the arc and to develop contacts that can withstand the effect of the arc time over time.
A vacuum circuit breaker uses the rapid dielectric recovery and high dielectric strength of the vacuum. The pair of contacts are hermetically sealed in the vacuum envelope. An actuating motion is transmitted through bellows to the movable contact. When the electrodes are parted, an arc is produced and supported by metallic vapor boiled from the electrodes. Vapor particles expand into the vacuum and condense on solid surfaces. At a natural current zero, the vapor particles disappear and the arc is extinguished.
In the past, in association with such wind farms, when collect circuit breakers are opened, the collection circuit voltage would be interrupted and a transient overvoltage situation could occur in the collection circuit. In the overvoltage situation, the high transient voltage in the collection circuit line will “back up” through the circuit and to the electronics associated with the wind energy generators. As a result, this transient overvoltage could cause damage to the circuitry associated with the wind energy generators and other circuitry throughout the system. As a result, in view of the characteristics of the large energy resident within by the overall wind energy farm, there is an extreme need to hold within acceptable limits any overvoltage which occurs when the circuit breaker is be opened.
Typically, to avoid the overvoltage situation, grounding transformers have been required to be installed. These grounding transformers would typically have 34.5 kilovolts on the primary winding with a 600 volts open delta secondary winding. The transformer has a core with windings therearound. In view of the core and windings, there was continuous amount of core losses of energy associated with the use of such grounding transformers. Over time, the core losses could amount to a significant dollar amount of lost energy. Additionally, these grounding transformers had a relatively high initial cost, installation cost, and a long lead time of delivery.
When a single line to ground fault occurs, there are basically two objectives for protecting the collection circuit. The first objective is clearing the fault from the grid to reduce both the incident energy and the time that personnel and equipment are exposed to the huge fault current sourced from the transmission system. When the feeder breaker operates first and clears the plant from the fault, high current from the transmission system is limited in time. However, the temporary overvoltage in the collection circuit can present a problem since the generator is islanding. The second objective is to get the generators to shut down without islanding. This object competes with the first objective of “quickly opening the feeder breaker”. It takes approximately 200 milliseconds for the signal to reach the generators in order for them in order to shut the generators down. Islanding occurs when all or a portion of the power generated by power plant becomes electrically isolated from the remainder of the electrical power system. For example, when a collection circuit producing power at 24 megawatts separates, severe islanding can occur. Some designers place a grounding transformer on the collection circuit when trying to avoid temporary overvoltage. In certain cases, however, the grounding transformer will not be effective when it comes to reducing temporary overvoltages and subsequent damage to the lightning arrestors. Grounding transformers connected to the collection circuits provide a zero sequence path to ground that does not provide a positive or negative sequence path to ground. Grounding transformers provide a relatively low zero sequence impedance. However, the impedance is not low enough to prevent a severe voltage rise during a fault followed by a severe islanding event.
Faults in collection circuits happen and the longer that a fault continues, the more damage will because. Although communication systems are fast, they do not process information instantaneously. Therefore, communication plays a very important role in protecting the collection circuit. A signal over a dedicated communication channel, such as a fiber, will take time to complete. This delay is called “latency”. Delays from the initiation of a fault on the collection circuit to the time when the equipment is separated or isolated from the fault is called “clearing time”. When protecting a collection circuit, among the objectives to be accomplished, it is necessary to clear the fault from the grid and clear the fault from the individual generators. The use of the transfer trip tool can be used. “Transfer trip” means the opening of a circuit breaker from a remote location by means of a signal over a communication channel. When using transfer trip, if the fault is cleared by the grid by tripping the feeder breaker as fast as possible and if the feeder breakers take longer than desired, the entire collection circuit is exposed to temporary overvoltage. If the feeder breaker is intentionally delayed in order to match the opening of the feeder breaker and the wind turbine generator breakers, the feeder is exposed to incident energy (in excess of 15,000 amps) and eventually the temporary overvoltage will occur if the delay is not sufficient.
The Federal Energy Regulatory Commission (FERC) has Reliability Standard PRC-024-1. Relay settings in wind and solar power plants must comply with the standard. The standard states that each generator that has generator voltage protective relaying activated to trip its applicable generating unit(s) shall set its protective relaying such that the generator voltage protective relaying does not trip the applicable generating unit(s) as a result of voltage excursion (at the point of interconnection) caused by an event on the transmission system external to the generating plant that remains within a “no trip zone” of a time duration curve. The point of interconnection means that the transmission (high-voltage) side of the generator step-up transformer or collector circuit transformer. Many types of faults occur within or outside of the wind power or solar power plant. An internal fault is considered as a single line fault to ground while an external fault is a three-phase bolted fault. Conventional ground transformers provide no way for the operator to ascertain whether the fault is internal or external. As a result, operation within the “no trip zone” may be required even though the fault is internal of the wind or solar farm. As such, a need has developed in order for the operator to ascertain whether the fault is internal or external of the wind or solar farm system.
When grounding transformers are not used, it is necessary to switch the current to ground extremely quickly. If the switch does not occur within a maximum of three cycles, then the overvoltage condition can occur. Ideally, to avoid any potential for an overvoltage situation, it is necessary to close the circuit to ground within one cycle, i.e. 16 milliseconds. Ultimately, experiments attempting to achieve electrical switching systems have indicated that the switching would occur at a level dangerously close to the five cycle limit. Preferably, it is desirable to cause the switching to occur in as close to an instantaneous manner as possible.
In the past, various patents and patent application publications have issued with respect to such circuit breakers. For example, U.S. Pat. No. 5,612,523, issued on Mar. 18, 1997 to Hakamata et al., teaches a vacuum circuit-breaker and electrode assembly. A portion of a highly conductive metal member is infiltrated in voids of a porous high melting point metal member. Both of the metal members are integrally joined to each other. An arc electrode portion is formed of a high melting point area in which the highly conductive metal is infiltrated in voids of the high melting point metal member. A coil electrode portion is formed by hollowing out the interior of a highly conductive metal area composed only of the highly conductive metal and by forming slits thereon. A rod is brazed on the rear surface of the coil electrode portion.
U.S. Pat. No. 6,048,216, issued on Apr. 11, 2000 to Komuro, describes a vacuum circuit breaker having a fixed electrode and a movable electrode. An arc electrode support member serves to support the arc electrode. A coil electrode is contiguous to the arc electrode support member. This vacuum circuit breaker is a highly reliable electrode of high strength which will undergo little change with the lapse of time.
U.S. Pat. No. 6,759,617, issued on Jul. 6, 2004 to S. J. Yoon, describes a vacuum circuit breaker having a plurality of switching mechanisms with movable contacts and stationary contacts for connecting/breaking an electrical circuit between an electric source and an electric load. The actuator unit includes at least one rotary shaft for providing the movable contacts with dynamic power so as to move to positions contacting the stationary contacts or positions separating from the stationary contacts. A supporting frame fixes and supports the switching mechanism units and the actuator unit. A transfer link unit is used to transfer the rotating movement of the rotary shaft to a plurality of vertical movements.
U.S. Pat. No. 7,223,923, issued on May 28, 2007 to Kobayashi et al., provides a vacuum switchgear. This vacuum switchgear includes an electro-conductive outer vacuum container and a plurality of inner containers disposed in the outer vacuum container. The inner containers and the outer container are electrically isolated from each other. One of the inner vacuum containers accommodates a ground switch for keeping the circuit open while the switchgear is opened. A movable electrode is connected to an operating mechanism and a fixed electrode connected to a fixed electrode rod. Another inner vacuum container accommodates a function switch capable of having at least one of the functions of a circuit breaker, a disconnector and a load switch.
U.S. Pat. No. 3,883,706, issued on May 13, 1975 to K. Glaser, describes a multiple rotary wafer type switch with axial bridging contacts and multiple wafer connecting rings. There are at least two circular insulating members each having a central opening. The members are assembled with end faces thereof being in contact and their openings in registry. Radially inwardly extending contact tongues are embedded in the insulating members for cooperation with the rotor having contact bridges arranged in the central openings. An elastically deformable connecting ring is disposed in the central openings and axially overlaps the insulating member.
U.S. Pat. No. 4,016,385, issued on Apr. 5, 1977 to I. Golioto, teaches a high-voltage transfer switch with a cam controlled overlap during transfer. This transfer switch selectively transfers an electrical load from one high-voltage source to another. The transfer switch includes a shaft connected to a handle. There are two circular slotted cams spaced close to opposite ends of the shaft. Cam followers are connected to opposite ends of a follower bar and are inserted in the cam slot. The follower bars connected to the cam follower are connected to vacuum interrupter contacts. The transfer switch is constructed so that as the cam is rotated, the contacts connecting one high-voltage source to the electrical load are closed and as the cam is continued to be rotated, the contactors of the previously connected high-voltage supply are subsequently released.
U.S. Pat. No. 6,462,296, issued on Oct. 8, 2002 to Boettcher et al., describes a circuit breaker arrangement and, in particular, and air-insulated medium-voltage switching arrangement having circuit breaking features, disconnection features and grounding features. The circuit breaker arrangement includes a switching module that is formed from function-oriented modular components. The modular components include abase module component, a pole module component and a drive module component. The base module component is fixedly connected with the drive module component. The pole module component is arranged so as to be movable along a straight line.
U.S. Pat. No. 6,951,993, issued on Oct. 4, 2005 to Kikukawa a et al., provides a vacuum switch having a vacuum container, a grounding switch, and a load switch disposed in a container. An external connection conductor is disposed in the vacuum container and connected electrically inside and outside of the vacuum container. The grounding switch and the external connection conductor are electrically connected to each other in the vacuum container.
U.S. Pat. No. 7,724,489, issued on May 25, 2010 to the present inventor, describes a circuit breaker with a high-speed mechanically-interlocked grounding switch. The subject matter of this patent is described hereinbelow.
U.S. Pat. No. 8,174,812, issued on May 8, 2012 to the present inventor, describes a mechanically interlocked transfer switch that has first, second and third electrical terminals extending outwardly from a housing. A first vacuum bottle is positioned in the housing and has a pair of contactors therein. A second vacuum bottle is positioned in the housing and has a pair of contactors therein. A mechanical linkage is movable between a first position and a second position. The first position electrically connects the first electrical terminal to the second electrical terminal. The second position electrically connects the third electrical terminal to the second electrical terminal. The first vacuum bottle in the second vacuum bottle are longitudinally aligned. The mechanical linkage is interposed between the first and second vacuum bottles.
U.S. Pat. No. 8,467,166, issued on Jun. 18, 2013 to the present inventor, describes a circuit breaker and impedance grounding switch having a first electrical terminal, a second electrical terminal, a third electrical terminal, a first vacuum bottle with a pair of contactors therein, a second vacuum bottle with a pair of contactors therein, and a mechanically interlocked linkage being electrically interconnected to the second electrical terminal and being movable between a first stable position and a second stable position. One of the pair of contactors of the first vacuum bottle is connected to the first electrical terminal. One of the pair of contactors of the second vacuum bottle is electrically interconnected to the third electrical terminal. The linkage has a temporary position between the first and second stable positions electrically connecting simultaneously the first electrical terminal to the second electrical terminal and a third electrical terminal to the second electrical terminal.
Japanese Patent No. 2000341858, published on Dec. 8, 2000, describes a device and method for switching a power supply. This device switches the power supply received by a dual system at high speed by opening the pole of a primary switch at a current zero point formed out of current supplied by primary and secondary power systems. It then turns off the primary switch from a primary power system and steps down the voltage to normal operating voltage. After a pole closing command is sent from a switching control part to the switch of the secondary power system, the pole closing of the switch is completed. A pole opening command is outputted from the switching control part to a primary switch. The pole is open so as to cut off current at a current zero point formed out of currents running from the primary and secondary current systems.
Japanese Patent No. 05174676, published on Jun. 26, 2000, teaches a power source change-over switch which simultaneously carries out change-over switching for selectively switching first and second power sources to connect them to the load. A first contact is provided between a first power source and a load. A second contact is switched complementarity to the first contact and is provided between the second power source and the load. The first contact is composed of a contact pair of a first fixed contact and a first moving contact. The second contact is composed of a contact pair of a second fixed contact and a second moving contact.
Japanese Patent No. 07161265, published on Jan. 26, 2004 describes an electrical power switching device that performs space saving without generating arc short-circuiting. A first auxiliary contactor is formed adjacent to a main contactor. A second auxiliary contactor is formed adjacent to a second main contactor when a switching command is given, the first main contactor is opened. Just after the first main contactor is opened and just before the auxiliary contactor is opened, a voltage drop is generated because the first current control element is inserted between the first power supply and the load.
Japanese Patent No. 2006019193, published on Jan. 19, 2006, describes a switching device that improves the insulation properties of the switching device to which a number of vacuum valves are connected serially. The device has a pair of contacts which are freely connected or disconnected. Two or more serially connected vacuum valves having an arc shield of intermediate potential is enclosed around the pair of contacts. Voltage share elements are connected in parallel between a contactor, the vacuum valve and the arc shield. An operating mechanism is provided for opening and closing the vacuum valve simultaneously.
Japanese Patent No. 11162303, published on Jun. 18, 1999, describes a switchgear intended to reduce the size of the switchgear. A fixed electrode for a main circuit is provided at one end of the inside of one vacuum ground vessel while a fixed electrode for a ground circuit is provided at the other end thereof. The number of each of the electrodes corresponds to the style of a single phase or multiphase system. A moving conductor connected to a load side conductor for each phase is insulation-supported between the fixed electrodes so that it can move linearly. A movable electrode for the main circuit is provided at one end of the moving conductor while the movable electrode for the ground circuit is provided at the other end thereof. A driver for moving the moving conductor is provided at the other side of the vacuum ground vessel.
European Patent Application No. 1 538 650, published on Jun. 8, 2005, teaches an isolator/circuit breaker device for electric substations. The device comprises a casing, at least one circuit breaker, at least one line isolator having a fixed isolator contact, a line isolator actuating shaft for actuating the line isolator, at least one earthing isolator, a circuit breaker actuating shaft for actuating at least one circuit breaker, and a lever connected to a conductor rod cooperating with movable circuit breaker contacts. The conductor rod engages with the fixed isolator contact in a closing position. The device further includes a resilient member cooperating with the conductor rod in order to transfer correct pressing loads to the movable contacts.
An important prior art reference is that of U.S. Pat. No. 7,724,489 to the present inventor. This patent describes a circuit breaker with a high-speed mechanically-interlocked grounding switch. This system 42 is shown in
As such, various busses 64 can also be connected to a main energy transfer bus 66. Ultimately, the energy is transmitted along line 68 to the circuit breaker 44. When the circuit breaker 44 is suitably closed, then the energy will be delivered along line 70 to substation 72. It can be seen in
The bushing 80 has another current transformer 84 extending therearound. Current transformer 84 is a configuration similar to that of current transformer 82. Current transformer 84 serves to sense the power and the quality of power passing outwardly of the circuit breaker 44 and to the substation. Once again, the current transformer 84 can be suitably interconnected to proper relays so as to open and close the circuit breaker 44 in the event of a problem condition.
A busbar 86 connects the bushing 78 to the mechanical interlock 88. The mechanical interlock 88 is interposed between a first vacuum bottle 90 and a second vacuum bottle 92. Another busbar 94 is located at the top of the first vacuum bottle 90 and extends in electrical connection to the second bushing 80. The second vacuum bottle 92 includes a grounding bar 96 suitably connected to ground. Supports 98, 100 and 102 will maintain the vacuum bottles 90 and 92, along with the mechanical interlock 88, in a longitudinally-aligned orientation extending substantially vertically within the interior of the housing 74. A suitable operating and communication mechanism 104 is cooperative with the mechanical interlock 88. Control push buttons and indicating lamps 106 are located on a wall of the enclosure 74 so as to provide a humanly perceivable indication of the operation of the circuit breaker 44 and allowing for manual control of the mechanical interlock 88. There is an auxiliary terminal block compartment 108 located on an opposite wall of the enclosure 74 from the control push buttons 106. The housing 74 is supported above the earth by legs 110 (or by other means).
In
In the event of an interruption, a failure, or a problem, the circuit breaker 44 will open the circuit to the substation so that the electrical energy passing through the busbar 86 is passed to ground 46 instantaneously. As can be seen in
It was found that the system of U.S. Pat. No. 7,724,489 was an extremely effective circuit breaker for use in wind or solar farm applications. The subject matter of U.S. Pat. No. 7,724,489 has been widely employed throughout the world in connection with wind farms. However, it was found that certain improvements can be made in the circuit breaker of U.S. Pat. No. 7,724,489 which allow the circuit breaker to achieve unique advantages and benefits.
Initially, the circuit breaker apparatus utilizes a very large enclosure. This large enclosure is required because of the longitudinal alignment of the vacuum bottles of the main circuit breaker and the grounding switch as well as separation between the three phases of the electrical system. As such, the enclosure which contains these vacuum bottles needs to have a significant height to accommodate this longitudinal alignment as well as a significant width to separate the three phases adequately. It was necessary to maintain this longitudinal alignment in order to avoid possible arcing events that could occur between the main circuit breaker and the grounding switch. Additionally, in view of the relatively tall configuration of the circuit breaker, it was necessary to extend the bushings outwardly of the top of the enclosure. These bushings would be connected to switch disconnects located thereabove and to the main bus located thereabove. As such, the installation of the circuit breaker of U.S. Pat. No. 7,724,489 had a significant height. As such, need developed so as to reduce the size of the circuit breaker apparatus.
It is an object of the present invention to provide a circuit breaker apparatus that has a relatively small housing and a small footprint.
It is another object of the present invention to provide a circuit breaker apparatus that is easier to transport and assemble.
It is a further object of the present invention to provide a circuit breaker apparatus that has the ability to differentiate between internal faults and external faults.
It is a further object of the present invention to provide a circuit breaker apparatus which can avoid the need to address certain no-trip zones.
It is a further object of the present invention to provide a circuit breaker apparatus that avoids islanding events.
It is another object of the present invention to provide a circuit breaker apparatus that eliminates concerns regarding cybersecurity.
It is a further object of the present invention to provide a circuit breaker apparatus that has better safety and reliability.
It is still another object of the present invention to provide a circuit breaker apparatus that eliminates temporary overvoltages.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The circuit breaker apparatus of the present invention comprises a housing, and electrical power inlet, an electrical power outlet, a main circuit breaker, a grounding switch, and a mechanical linkage. The main circuit breaker is positioned in the housing. The main circuit breaker has a pair of contactors therein. One of the pair of contactors is electrically connected or interconnected to the electrical power inlet and to the electrical power outlet. The grounding switch is also positioned in the housing. The grounding switch has a pair of contactors therein. One of the pair of contactors of the grounding switch is electrically connected or interconnected to ground. The grounding switch is in a non-longitudinal relation to the main circuit breaker. The mechanical linkage is movable between a first position and a second position. The first position actuates the main circuit breaker such that the pair of contactors of the main circuit breaker are closed and such that pair of contactors of the grounding switch are opened. The mechanical linkage is movable to a second position so as to actuate the main circuit breaker such that the pair of contactors of the main circuit breaker open and such that the pair of contactors of the grounding switch are closed.
In the preferred embodiment of the present invention, the housing has an interior that is filled with air.
The electrical power outlet has a main bus having at least a portion positioned in the housing. The main circuit breaker is electrically connected to the main bus when the pair of contacts of the main circuit breaker are closed. A switch disconnect is also positioned in the housing. The switch disconnect is movable between a first position which electrically connects the main circuit breaker to the main bus and a second position electrically isolating the main circuit breaker from the main bus. The grounding switch extends in generally transverse relationship to the main circuit breaker.
The mechanical linkage includes an actuator that is movable between a first position that a second position. The actuator is movable from the first position to the second position upon detection of a fault in electrical power from the electrical power inlet. A yoke is connected to the actuator. The yoke is connected to one of the pair of contactors of the main circuit breaker and one of the pair of contactors of the grounding switch. A movement of the actuator to the second position causes the pair of contactors of the main circuit breaker to open and the pair of contactors of the grounding switch to close. The yoke is pivotally mounted within the housing. The yoke has a generally L-shape. The actuator has an arm connected to one end of the L-shape of the yoke. One of the pair of contactors of the grounding switch is connected to a portion of the L-shape away from the one end of the L-shape. One of the pair of contactors of the main circuit breaker is connected to an opposite end of the L-shape. The actuator has a rod connected to the arm in a location away from one end of the L-shape. The rod is resiliently mounted so as to move downwardly upon a detection of a fault in the electrical power from the electrical power inlet. The downward movement causes the rod to move the arm so as to pivot the yoke in order to open the pair of contactors of the main circuit breaker and close the pair of contactors of the grounding switch.
The main circuit breaker has a vacuum bottle in which the pair of contactors are positioned. The grounding switch also has another vacuum bottle in which the pair of contactors are positioned.
The electrical power inlet includes a cable extending to or into the housing, a conductor connected to the cable through a bushing, and a conductive plate positioned in the housing adjacent to the main circuit breaker. The main circuit breaker is electrically connected to the conductive plate.
A grounding bus is connected to another of the pair of contactors of the grounding switch. The grounding bus is connected to the ground so that the electrical power passes to ground when the pair of contactors of the main circuit breaker open and when the pair of contactors of the grounding switch are closed. One of the pair of contactors the main circuit breaker is movable while another of the pair of contactors of the main circuit breaker is fixed. One of the pair of contactors of the grounding switch is movable while another of the pair of contactors of the grounding switch is fixed.
In the present invention, the electrical power inlet passes power of three phases. The main circuit breaker comprises three main circuit breakers respectively connected to the three phases. The grounding switch is respectively connected to the three phases. The mechanical linkage comprises three mechanical linkages respectively connected to the three main circuit breakers and the three grounding switches.
The housing has a gas release valve affixed thereto. The gas release valve is movable between an open position and a closed position. The gas release valve is movable to the open position when an arc or an explosion occurs within the housing. The housing has an enclosed channel cooperative with the gas release valve so as to conduct hot gas outwardly when said gas release valve is in the open position.
The present invention is also a switchgear having a plurality of the circuit breakers connected together. The electrical power outlet is a main bus that extends between the plurality of circuit breaker apparatuses.
This foregoing Section is intended to describe, with particularity, the preferred embodiments of the present invention. It is understood that modifications to these preferred embodiments can be made within the scope of the present claims. As such, this Section should not to be construed, in any way, as limiting of the broad scope of the present invention. The present invention should only be limited by the following claims and their legal equivalents.
Referring to
In
The mechanical linkage 230 includes an actuator 232 that is movable between a first position and a second position. The actuator 232 is movable from the first position to the second position upon detection of a fault in the electrical power from the electrical power inlet 214. A yoke 234 is pivotally mounted within the interior 208 of housing 202. The yoke is connected to one of the pair of contactors of main circuit breaker 210 and one of the contactors of the grounding switch 212. A movement of the actuator 232 to the second position causes the pair of contactors of the main circuit breaker 210 to open and the pair of contactors of the grounding switch 212 to close.
It can be seen that the yoke 234 has a generally L-shape. The actuator 232 is connected adjacent to one end of the L-shape of the yoke 234. One of the pair of contactors of the grounding switch is connected to a portion of the L-shape away from one end of the L-shape. One of the pair of contactors of the main circuit breaker 210 are connected to an opposite end of the L-shape. The actuator 232 includes a rod 236 that is connected to the arm 238 at a location from one end of the L-shape of the yoke 234. The rod 236 is resiliently mounted so as to move downwardly upon the detection of a fault in the electrical power from the electrical power inlet 214. The downward movement of the rod 236 causes the rod 236 to move the arm 238 in order to pivot the yoke 234 in order to open the pair of contactors of the main circuit breaker 210 and to close the pair of contactors of the grounding switch 212.
The main circuit breaker 210 has a vacuum bottle in which the pair of contactors are positioned. Similarly, the grounding switch 212 has another vacuum bottle in which the pair of contactors of the grounding switch are positioned.
A main bus 240 is located in an upper portion of the housing 202. An isolator, namely switch disconnect 242, is cooperative with the main bus 240. The main bus 240 has at least a portion positioned within the housing 202. This main bus can extend outwardly of the housing 202 so as to connect with other circuit breaker apparatus, such as circuit breaker apparatus 200. As such, it can be used to form a suitable switchgear (as will be shown in
The main circuit breaker 210 is electrically connected to the main bus 240 when the pair of contactors of the main circuit breaker 210 are closed. The switch disconnect 242 is positioned in the housing 202. The switch disconnect is movable between a first position in which the main circuit breaker 210 is electrically connected to the main bus 240 and a second position in which the main bus 240 is electrically isolated from the main circuit breaker 210. In particular, there is a contact blade 244 that is connected to a linkage 245 so as to be mechanically or manually operated so as to move the switch disconnect 242 between the first position and the second position. A movement of the contact blade 244 and the linkage 245 in one direction will separate the switch disconnect 242 so that the switch disconnect 242 is in the second position. The contact blade 244 and the linkage 245 can be rotated or manipulated in an opposite directions so as to urge the switch disconnect 242 upwardly so as to electrically connect with the main bus 240.
An insulated support 247 retains the main bus 240 in a proper horizontal orientation within the interior 208 of the housing 202. Another insulated support 249 maintains the switch disconnect 242 in a proper position in the interior 208 of the housing 202. Another insulated support 251 supports the contact blade 244 (along with the linkage 245) within the housing 202. Insulated support 253 supports the conductor 255 that is connected to the main circuit breaker 210. Insulated supports 249 and 253 extend over the bus that extends from the main circuit breaker 210 to the switch disconnect 242 and the main bus 240. A frame 257 is positioned within the interior 208 of the housing 202 so as to structurally support current transformers for relaying and metering purposes. Another insulated support 259 extends inwardly from a wall of the housing 202 so as to support an end of the conductor 255 and to support the main circuit breaker 210 within the housing 202.
In
Unlike the subject matter of U.S. Pat. No. 7,723,489, it is important to note that the switch disconnect 242 and main bus 240 are located within the interior of the housing. As such, the bushings associated with the prior art are avoided in the present invention along with the complex arrangement of the switch disconnects and the main bus at a location above the circuit breaker apparatus. As such, the present invention provides a very compact configuration. This reduces size, transportation costs, manpower required for assembly, materials, along with a variety of other cost savings.
Unlike the subject matter of U.S. Pat. No. 7,724,489, the main circuit breaker 210 and the grounding switch 212 are placed in non-longitudinal alignment and the three phases of power can be placed in close proximity to each other. As such, the height and the width of the housing are greatly reduced and the space required for the operating mechanisms within the housing are also significantly reduced.
Simulation shows that the circuit breaker apparatus of the present invention resolves both issues of temporary overvoltage and incident energy where delays are not needed for clearing the fault from the plant. The present invention completely operates within nearly fifty milliseconds to open, clear the fault, close, and ground the affected collection circuit. As such, it collapses the voltage. When closed to ground, the present invention results in a very low impedance in the cable. There is a very clear change in impedance as it operates. Generators can detect such a change and act on it. The temporary overvoltage duration is minimized by the combination of the fast transition state of the present invention and the lightning arrestors. The present invention significantly lowers the energy burden on lightning arrestors and protects them. The present invention relieves the lightning arrestor and keeps the resulting temporary overvoltage below the duty curves. Without the present invention, the arrestors could be destroyed by other protection schemes. If they are destroyed and not replaced, expensive collection circuit equipment could be damaged thereinafter.
The circuit breaker apparatus the present invention signals the wind generators in a fraction of the 150 ms required by PRC-024-1 and PRC-024-2 when the fault is inside the plant. This provides the generators with valuable information in which to allow the decision to be made to shut down. The present invention signals the generator that the fault is inside the plant and shuts them down for events that the turbines should not ride through. This provides a valuable discriminatory function that standard circuit breakers would not. The present invention forms a three-phase bolted ground and provides a zero reference closer to the generators than the zero reference that forms with the three-phase bolted ground at the point of interconnection. The difference in impedance between internal faults and external faults is basically the impedance of the main plant transformer. At near full power for the wind or solar power plant, the delta in voltage between the two fault locations is approximately eight percent. As a result, each generator can detect and discriminate between each fault location. Because the present invention can help differentiate between internal and external faults, generators will know via, the voltage measured at their terminals, that the fault is outside the plant and keep it running. As a result, the present invention provides designers and engineers with the ability to distinguish between external and internal faults. As such, the generators may be set to trip if the fault is in the plant or ride through the fault if the fault is outside the plant. The present invention does not require the use of fiberoptic installations that link the substation with the turbines to send shutdown signals to the generator. As such, the present invention is extremely cybersecure. The shutdown signal goes from the present invention to all of the generators of the collection circuit faster than any other means and the signal is transmitted to all of the generators at the same time.
The present invention protects solar/wind power plants by reducing incident energy and eliminating temporary overvoltage. Elimination of the temporary overvoltage is an important feature of the present invention. Through the present invention, the lightning arrestors are operated below their prior duty curve, insulation coordination of the feeder circuit is maintained, and the equipment becomes more reliable. The present invention has an anti-island functionality. Unlike the prior art, the present invention avoids the islanding effect.
The foregoing disclosure and description of the present invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
The present application is a continuation-in-part of U.S. patent application Ser. No. 16/455,306, filed on Jun. 27, 2019, and entitled “Gas Insulated Grounding Switch”, presently pending.
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