Patent Description:
The present application generally relates to electrical systems, and more particularly, but not exclusively, to surge arrester systems and circuit breaker systems.

Surge arrester systems and circuit breaker systems of various types remain an area of interest. Some existing systems have various shortcomings, drawbacks and disadvantages relative to certain applications. For example, in some systems, cooling for the surge arrester may be improved. Accordingly, there remains a need for further contributions in this area of technology.

Prior art <CIT> discloses a circuit breaker, which includes a plurality of stacked breaker modules arranged in series. Each breaker module can include, in parallel, a mechanical switching assembly, a semiconductor switching assembly and an arrester assembly. The arrester assembly thereby comprises at least one surge arrester. The circuit breaker can easily be adapted to a larger number of applications and voltage ranges by varying the number of breaker modules. Further, an active cooling system is disclosed, which includes a forced air convection.

Prior art <CIT> discloses a surge arrester system according to the preamble of claim <NUM>.

The present invention relates to a surge arrester system having the features of claim <NUM>. Further, a circuit breaker system comprising such a surge arrester is specified in claims <NUM> and <NUM>. Preferred embodiments of the invention are specified in the dependent claims.

Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.

The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:.

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same.

Referring to <FIG>, some aspects of a non-limiting example of a surge arrester system <NUM> in accordance with an embodiment of the present invention are schematically illustrated. Surge arrester system <NUM> includes a surge arrester <NUM>, and a first active cooling system <NUM>. The surge arrester <NUM> is a metal oxide varistor (MOV). The surge arrester system <NUM> also includes second active cooling system <NUM>. Active cooling system <NUM> includes a cooling interface <NUM> for interfacing with one or more components sought to be cooled, e.g., with surge arrester <NUM> in the embodiment of <FIG> (and/or power semiconductors in other embodiments). In some embodiments, active cooling system <NUM> also includes a base unit <NUM>. Base unit <NUM> may be integral with cooling interface <NUM> or may be located separately from cooling interface <NUM>.

Cooling interface <NUM> for each active cooling system <NUM> is in contact with surge arrester <NUM>, one on each side of surge arrester <NUM>, and is operative to transfer heat from surge arrester <NUM>. Active cooling system <NUM> does not rely on natural convention, but rather, relies on forced convection in one or more forms. For example, in various embodiments, active cooling system <NUM> includes a forced convection apparatus <NUM>, e.g., a fan or a pump or a pressurized coolant source or other device or system that provides forced convection flow for removing heat via forced convection, i.e., provides forced convection cooling. Forced convection apparatus <NUM> is the active portion of active cooling system <NUM>. Base unit <NUM> and/or cooling interface <NUM> are passive portions of active cooling system <NUM>.

Forced convection apparatus <NUM> forces a gas or a liquid through or against base unit <NUM> and/or cooling interface <NUM> and/or another component in order to transfer heat <NUM> away from surge arrester <NUM>. In other embodiments, forced convection unit <NUM> forces a gas or a liquid through or against base unit <NUM> and/or cooling interface <NUM> in order to transfer heat <NUM> away from another electrical component, e.g., a solid state circuit breaker or one or more power semiconductors, e.g., used to form all or a part of a solid state circuit breaker, in addition to or in place of surge arrester <NUM>, e.g., depending upon the embodiment. In some embodiments, forced convection apparatus <NUM> may be located separately from base unit <NUM>, and in other embodiments, may be or be a part of base unit <NUM>.

In one form, active cooling system <NUM> includes a pulsating heat pipe (PHP) with a single condenser, e.g., wherein the PHP is a passive component of active cooling system <NUM>, and the active component is a separately located fan or pump used to circulate air or another fluid over the condenser, e.g., forced convection apparatus <NUM>. For example, in some such embodiments, the base unit <NUM> is the condenser of the PHP, cooled by forced convection apparatus <NUM>, and the cooling interface <NUM> is the evaporator or a thermally conductive pad or mount that is, for example, closely thermally coupled to the evaporator of the PHP. In other embodiments, active cooling system <NUM> may take other forms, and may include, for example, a water cooler or cold plate system, an air cooler system, a two-phase thermosiphon heat exchanger, a pulsating heat pipe, and/or a loop heat pipe (LHP). The cooling element, e.g., cooling interface, may be, for example, a refrigerant pulsating heat pipe with a single condenser, a refrigerant pulsating heat pipe with a double condenser, a heat sink, e.g., cooled with forced convection, an insulated base to water pulsating heat pipe, a cold plate, or an evaporator. In some embodiments, two or more active cooling systems <NUM> may share one or more forced convection apparatuses <NUM>.

Referring to <FIG> some aspects of a non-limiting example of a circuit breaker system <NUM> in accordance with an embodiment of the present invention are schematically illustrated. Circuit breaker system <NUM> supplies power from a source <NUM> to a load <NUM>, with the inductance of the system represented as Lsys. Circuit breaker system <NUM> includes surge arrester <NUM> in the form of an MOV in parallel with two power semiconductors <NUM> disposed antiparallel to each other. In one form, power semiconductors are solid state switches.

Referring to <FIG> some aspects of a non-limiting example of a circuit breaker system <NUM>, e.g., a realization of the circuit breaker system <NUM> of <FIG>, in accordance with an embodiment of the present invention is illustrated. In one form, circuit breaker system <NUM> is configured to handle power requirements between 50V and 2000V, and between 100A and 5000A. In other embodiments, other circuit breaker systems may be configured to handle power requirements above or below this range. Circuit breaker system <NUM> includes a surge arrester <NUM>; two (<NUM>) power semiconductors <NUM>; four (<NUM>) active cooling systems <NUM> (e.g., as described above with respect to <FIG>); two (<NUM>) insulators <NUM> and a clamping mechanism <NUM> having clamping end structures <NUM> held together in a clamping arrangement by clamp bolts <NUM> and retaining nuts <NUM>. In one form, power semiconductors <NUM> are integrated gate commutated thyristors (IGCTs). In other embodiments, other types of power semiconductors may be used in addition to or in place of IGCTs. This may result in a different configuration and number of power semiconductors <NUM>, e.g., one, two or more power semiconductors <NUM> may be employed in any suitable configuration or topology. Other types of suitable power semiconductors include, for example, one or more integrated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), thyristors, and/or gate turn-off thyristors (GTOs), to name a few. As is illustrated in <FIG>, clamping mechanism <NUM> clamps surge arrester <NUM>, power semiconductors <NUM> and active cooling systems <NUM> (e.g., cooling interfaces <NUM> of active cooling systems <NUM>) together between insulators <NUM> to form a stack. The circuit realization of <FIG> is obtained using bus bars (not shown) coupling surge arrester <NUM> and power semiconductors <NUM> together and to the source <NUM> and load <NUM> (not shown).

Active cooling systems <NUM> are constructed to cool the plurality of power semiconductors <NUM>, and include a forced convection apparatus <NUM> configured to provide forced convection cooling for cooling power semiconductors <NUM> and surge arrester <NUM>. Power semiconductors <NUM> are sandwiched between the plurality of active cooling systems <NUM> (e.g., between cooling interfaces <NUM> of active cooling systems <NUM>). Surge arrester <NUM> is disposed adjacent to and in contact with at least one active cooling system <NUM> of the plurality of active cooling systems. The at least one active cooling system <NUM> includes a cooling interface <NUM> configured for contact with surge arrester. In the embodiment of <FIG>, surge arrester <NUM> is disposed adjacent to and in contact with two active cooling systems <NUM>.

Active cooling systems <NUM> include a forced convection apparatus <NUM> in the form of a fan, although in other embodiments, forced convection apparatus <NUM> may take other forms, e.g., a pump, such as wherein the active cooling system <NUM> is a water cooler or a cold plate. In the embodiment of <FIG>, active cooling systems <NUM> are include pulsating heat pipes with single condensers, although active cooling systems <NUM> may alternatively take other forms, e.g., as mentioned above with respect to the embodiment of <FIG>. In the embodiment of <FIG>, base units <NUM> are in the form of radiators (condensers), which receive cooling air <NUM> from forced convection apparatus <NUM> in order to provide forced convection cooling. In the embodiment of <FIG>, both the surge arrester <NUM> and the power semiconductors <NUM> receive double-sided cooling, that is, they are in contact with and cooled on both sides by adjacent active cooling systems <NUM> (e.g., adjacent cooling interfaces <NUM> of active cooling systems <NUM>). In one form, the cooling of surge arrester <NUM> is incidental to the cooling of power semiconductors <NUM>, because, as discussed below, surge arrester <NUM> and power semiconductors <NUM> do not dissipate power at the same time, and hence, only surge arrestor <NUM> or power semiconductors <NUM> dissipate power into active cooling system <NUM> at any given time.

Because surge arrester <NUM> is actively cooled, i.e., cooled using forced convection, the rate at which it can dissipate energy is augmented relative to cooling solutions that rely on natural convection cooling, e.g., natural convection alone. By providing enhanced cooling via forced convection, the energy dissipation rate for surge arrester <NUM> is increased, without requiring surge arrestor <NUM> to be oversized in order to handle the thermal loading. By bringing down the temperature of surge arrester <NUM> after a shot (i.e., an energy shot that must be dissipated by surge arrester <NUM>) using forced convection cooling, consecutive shots can be absorbed, e.g., without exceeding the operating temperature of surge arrester <NUM> in some embodiments. This is particularly desirable in the application of a circuit breaker with reclosing function. In some embodiments, in a reclosing cycle having three (<NUM>) surge arrester openings every three (<NUM>) seconds, double sided active cooling (forced convection cooling) can reduce surge arrester energy requirements and size by <NUM>% or more, compared to natural convection cooling.

In the circuit breaker application of <FIG>, active cooling (forced convection cooling) is already required for the thermal management of the power semiconductors <NUM>, i.e., in order to adequately cool power semiconductors <NUM>. By integrating surge arrester <NUM> into the thermal system of the power semiconductors <NUM>, surge arrester <NUM> does not need a dedicated cooling system, since the power semiconductors <NUM> and the surge arrester <NUM> dissipate power alternatively, i.e., they dissipate power into active cooling system <NUM> at different times, and thus the active cooling systems <NUM> are only used at any given time by either surge arrester <NUM> or the power semiconductors <NUM>. For example, power semiconductors <NUM> dissipate power into active cooling systems <NUM> during normal operation when power is being delivered via power semiconductors <NUM> to load <NUM>, during which time surge arrester <NUM> is effectively not transmitting current to load <NUM>, and thus is not dissipating power into active cooling system <NUM>. In circumstances where power semiconductor switches <NUM> are opened, system inductance L may cause voltage to rise, and surge arrestor <NUM> may conduct effectively as a resistor, and may dissipate power into active cooling system <NUM>, at which time power semiconductors <NUM> are not conducting, and hence are not dissipating power into active cooling systems <NUM>. Thus, active cooling of surge arrester <NUM> can be realized using the active cooling systems <NUM> designated for power semiconductors <NUM>.

Referring to <FIG>, a comparison plot <NUM> illustrates a reclosing event involving three (<NUM>) openings of the circuit breaker caused by three (<NUM>) shots of <NUM> kJ at intervals of three (<NUM>) seconds, and compares the temperature rise of a surge arrester with natural convection cooling with the temperature rise of a surge arrester with active cooling. The temperature rise <NUM> of the surge arrester with natural convection cooling is substantially greater than the temperature rise <NUM> of the surge arrester with active cooling, and exceeds the temperature limit <NUM> for the surge arrester after three (<NUM>) consecutive <NUM> kJ shots spaced apart by three (<NUM>) seconds each. Thus, a surge arrester using natural convection cooling would need to be over-dimensioned in order to reliably accomplish a reclosing function under such conditions. However, the surge arrester with active cooling easily dissipates the energy associated with the consecutive <NUM> kJ shots, and would thus not require any over-dimensioning.

It is desirable to test multiple operations of a circuit breaker system with a <NUM> second interval at nominal current, and a <NUM> second interval at short circuit current. Referring to <FIG>, a comparison plot <NUM> illustrates a comparison between natural convection cooling and active cooling in a test of multiple openings with <NUM> seconds between openings at nominal current conditions. Comparison plot <NUM> illustrates that the temperature rise <NUM> for a surge arrester with natural cooling is substantially greater than the temperature rise <NUM> for a surge arrester with active cooling. Referring to <FIG>, a comparison plot <NUM> illustrates a comparison between natural convection cooling and active cooling in a test of multiple openings with <NUM> seconds between openings at short circuit current conditions. Comparison plot <NUM> illustrates that the temperature rise <NUM> for a surge arrester with natural cooling is substantially greater than the temperature rise <NUM> for a surge arrester with active cooling. Thus, from <FIG>, it is seen that by providing active cooling, the temperature of a surge arrester with active cooling during repetitive operation is substantially lower than the temperature of the surge arrester with natural convection cooling under the same operating conditions.

Referring to <FIG>, some aspects of a non-limiting example of a circuit breaker system <NUM>, e.g., another realization of the circuit breaker system <NUM> of <FIG>, in accordance with an embodiment of the present invention is illustrated. The circuit realization of <FIG> is obtained using bus bars (not shown) coupling surge arrester <NUM> and power semiconductors <NUM> together and to the source <NUM> and load <NUM> (not shown in <FIG>). The embodiment of <FIG> is similar to the embodiment of <FIG>, except that in the embodiment of <FIG>, a quantity of three (<NUM>) active cooling systems <NUM> are employed instead of the quantity of four (<NUM>) that are employed in the embodiment of <FIG>. Like the embodiment of <FIG>, each solid state switch <NUM> has double-sided cooling, but unlike the embodiment of <FIG>, surge arrester <NUM> has single-sided cooling in the embodiment of <FIG>.

Referring to <FIG>, some aspects of a non-limiting example of a circuit breaker system <NUM>, e.g., another realization of the circuit breaker system <NUM> of <FIG>, in accordance with an embodiment of the present invention is illustrated. The circuit realization of <FIG> is obtained using bus bars (not shown) coupling surge arrester <NUM> and power semiconductors <NUM> together and to the source <NUM> and load <NUM> (not shown in <FIG>). The embodiment of <FIG> is similar to the embodiment of <FIG>. In the embodiment of <FIG>, active cooling systems <NUM> have cooling interfaces <NUM> in the form of water coolers or cold plates <NUM> coupled to forced convection apparatuses <NUM> in the forms of pumps. Forced convection apparatuses <NUM> pump cooled water into water coolers <NUM> to transfer heat from and provide forced convection cooling for surge arrester <NUM> and power semiconductors <NUM>. Some embodiments may include a radiator and fan for cooling the water that is used to cool surge arrester <NUM> and power semiconductors <NUM>. As with the embodiment of <FIG>, in the embodiment of <FIG>, power semiconductors <NUM> and surge arrester <NUM> are sandwiched between active cooling systems <NUM> and receive double sided forced convection cooling from active cooling systems <NUM>.

Referring to <FIG>, some aspects of a non-limiting example of a circuit breaker system <NUM>, e.g., another realization of the circuit breaker system <NUM> of <FIG>, in accordance with an embodiment of the present invention is illustrated. The circuit realization of <FIG> is obtained using bus bars (not shown) coupling surge arrester <NUM> and power semiconductors <NUM> together and to the source <NUM> and load <NUM> (not shown in <FIG>). The embodiment of <FIG> includes a surge arrester <NUM>, two (<NUM>) power semiconductors <NUM>; four (<NUM>) insulators <NUM>; and two (<NUM>) active cooling systems <NUM>. Active cooling system <NUM> have cooling interfaces <NUM> in the form of cooled heat sinks <NUM>. Two forced convection apparatuses <NUM> in the form of fans blow cooling air <NUM> over heat sinks <NUM> to provide forced convection cooling. Two (<NUM>) clamping mechanisms <NUM> are employed to clamp cooled heat sinks <NUM>, surge arrester <NUM> and power semiconductors <NUM> between insulators <NUM>.

Embodiments of the present invention include a surge arrester system, comprising: a surge arrester; and an active cooling system having a cooling interface in contact with the surge arrester and operative to transfer heat from the surge arrester, wherein the active cooling system includes a forced convection apparatus operative to provide forced convection cooling.

In a refinement the cooling interface is disposed on a first side of the surge arrester, and the surge arrester further comprises another active cooling system having another cooling interface in contact with the surge arrester and disposed on a second side of the surge arrester opposite to the first side, wherein the other cooling interface is operative to transfer heat from the surge arrester.

In another refinement, the forced convection apparatus is a fan or a pump.

In yet another refinement, the active cooling system includes a heat pipe system.

In still another refinement, the heat pipe system is a pulsating heat pipe system.

Embodiments of the present invention include a circuit breaker system, comprising: a power semiconductor switch; an active cooling system constructed to cool the power semiconductor switch, wherein the active cooling system includes a forced convection apparatus configured to provide forced convection cooling; and wherein the power semiconductor switch is in contact with the active cooling system; and a surge arrester disposed adjacent to and in contact with the active cooling system, wherein the active cooling system includes a cooling interface constructed for contact with the surge arrester and operative to provide cooling to the surge arrester, wherein the power semiconductor switch and the surge arrester dissipate power alternatively.

In a refinement, the circuit breaker system further comprises a plurality of insulators.

In another refinement, the power semiconductor switch, the active cooling system and the surge arrester are clamped together between the plurality of insulators.

In embodiment of the present invention, the active cooling system is a first active cooling system, further comprising a second active cooling system, wherein the surge arrestor is disposed adjacent to and clamped between the first active cooling system and the second active cooling system.

In still another refinement, the active cooling system includes a heat pipe system.

In yet still another refinement, the heat pipe system includes a pulsating heat pipe system.

In a further refinement, the active cooling system includes a water cooler or a cold plate.

In a yet further refinement, the active cooling system includes a cooled heat sink.

In a still further refinement, the forced convection apparatus is a fan or a pump. Embodiments of the present invention include a circuit breaker system, comprising: a plurality of power semiconductors; a plurality of active cooling systems configured to cool the plurality of power semiconductors, wherein the plurality of active cooling systems includes a fan or a pump configured to provide forced convection cooling; and wherein an active cooling system of the plurality of active cooling systems is disposed on at least one side of and in contact with each power semiconductor; and a surge arrester disposed adjacent to and in contact with the plurality of cooling systems; at least two insulators; and a clamp mechanism operative to clamp the plurality of power semiconductors, the plurality of active cooling systems and the surge arrester between the at least two insulators.

In a refinement, the surge arrestor is disposed adjacent to and clamped between two active cooling systems of the plurality of cooling systems.

In another refinement, the plurality of active cooling systems includes a plurality of heat pipe systems.

In yet another refinement, the plurality of heat pipe systems includes pulsating heat pipe systems.

In still another refinement, the plurality of active cooling systems includes a plurality of water coolers or cold plates.

Claim 1:
A surge arrester system (<NUM>), comprising:
a surge arrester (<NUM>) and
a first active cooling system (<NUM>) having a first cooling interface (<NUM>) and a first active cooling device, the first cooling interface (<NUM>) being disposed on a first side of the surge arrester (<NUM>) and operative to transfer heat from the surge arrester (<NUM>); characterized in that
the surge arrester (<NUM>) comprises a metal oxide varistor; and
the surge arrester system (<NUM>) further comprises
a second active cooling system (<NUM>) having a second cooling interface (<NUM>) disposed on a second side of the surge arrestor (<NUM>) and operative to transfer heat from the surge arrester (<NUM>), the second side and the first side being different sides of the surge arrestor (<NUM>),
wherein the first and and the second active cooling system (<NUM>) includes a forced convection apparatus (<NUM>) operative to provide forced convection cooling,
wherein the second side of the surge arrester is opposite the first side such that the surge arrester (<NUM>) is positioned between the first cooling interface (<NUM>) and the second cooling interface (<NUM>).