Switch cabinet overload automatic heat dissipation protection circuit

Abstract

The utility model discloses a switch cabinet overload automatic heat radiation protection circuit which is characterized in that the switch cabinet overload automatic heat radiation protection circuit comprises an overcurrent starting loop, the overcurrent starting loop is connected with a power supply through an air switch, and the overcurrent starting loop comprises a current relay LJ and an intermediate relay KA1; a starting loop and a self-holding loop; and the fan operation monitoring loop comprises an intermediate relay KA2 and an intermediate relay KA3, and the loop is connected with the starting loop in parallel. The utility model relates to the technical field of electric power equipment, which is characterized in that exhaust fans are respectively arranged in functional compartments (such as a bus chamber, a circuit breaker chamber and a cable chamber) of a power distribution cabinet, a current relay is connected in series in a current measurement loop, the load is monitored through the current relay, and when the load reaches a specified value set by the current relay, the exhaust fans are switched on. Therefore, heat dissipation fans installed in each function chamber of the switch cabinet can be started for air exhaust and heat dissipation.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment, in particular to an overload automatic heat dissipation protection circuit for a switch cabinet. Background Art

[0002] The power distribution cabinet used in the power industry is mainly composed of circuit breakers, busbars, and secondary control components. Among them, the busbar is the most affected by load, temperature, etc. The temperature of the busbar can gradually increase with the increase of load and temperature during use. The heat it emits will cause the overall temperature inside the entire switch cabinet to rise and the insulation material to melt, thus causing serious impact on the reliability, stability, and durability of the switch cabinet power supply and distribution. Utility Model Content

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies in the prior art, the utility model provides an automatic heat dissipation protection circuit for overload of a switch cabinet, which solves the problem of poor heat dissipation effect of the existing power distribution cabinet.

[0005] (II) Technical solution

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a switch cabinet overload automatic heat dissipation protection circuit, including an overcurrent starting circuit, which is connected to the power supply through an air switch, and the overcurrent starting circuit includes a current relay LJ and an intermediate relay KA1.

[0007] Starting circuit and self-holding circuit.

[0008] The fan operation monitoring circuit includes intermediate relay KA2 and intermediate relay KA3, and this circuit is connected in parallel with the starting circuit.

[0009] The fan operation indicator light circuit includes the signal light HR and the intermediate relay KA3.

[0010] The power-off delay circuit includes a time relay SJ and an intermediate relay KA1.

[0011] The fan operation circuit in the busbar room includes the fan FJ and the AC contactor KM.

[0012] The fan operation circuit in the circuit breaker room includes the fan FJ and the AC contactor KM.

[0013] The fan operating circuit in the cable room includes the fan FJ and the AC contactor KM.

[0014] As a further preferred embodiment, the starting circuit includes an automatic starting circuit and a manual starting circuit. The automatic starting circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA1. The manual starting circuit includes an AC contactor KM. The automatic starting circuit and the manual starting circuit are switched by an automatic / manual conversion switch.

[0015] As further preferred, the self-holding circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA2.

[0016] As a further preferred embodiment, the intermediate relay KA3 in the fan operation monitoring circuit is connected in parallel with the AC contactor KM.

[0017] (III) Beneficial effects

[0018] The utility model provides a switch cabinet overload automatic heat dissipation protection circuit. It has the following beneficial effects:

[0019] The switch cabinet overload automatic heat dissipation protection circuit is to set exhaust fans in each functional compartment of the power distribution cabinet (such as busbar room, circuit breaker room, cable room), connect a current relay in series in the current measurement circuit, and monitor the load size through this current relay. When the load reaches the specified value set by the current relay, the heat dissipation fan installed in each functional compartment of the switch cabinet can be started for exhaust and heat dissipation. When the current is restored to below the set specified value after exhaust cooling or load reduction, the heat dissipation fan can automatically stop working, and this cycle is repeated to ensure the normal working temperature inside the power distribution cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the control circuit schematic diagram of the utility model;

[0021] Figure 2 This is a current measurement circuit of the utility model.

[0022] In the figure: L, N: working power supply; ZK: air switch; SA: automatic / manual conversion switch; LJ: current relay; KA1~3: intermediate relay; KM: AC contactor; SJ: time relay; HR: signal light; FJ: fan; TAa~c: current transformer; LJ: current relay; A: measuring instrument; PE: grounding point. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] like Figure 1-2 As shown, the utility model provides a technical solution: an automatic heat dissipation protection circuit for overload of a switch cabinet, comprising an overcurrent starting circuit, which is connected to a power supply through an air switch ZK, and the overcurrent starting circuit comprises a current relay LJ and an intermediate relay KA1.

[0025] Figure 1 It is a current measurement circuit, TAa~c are three-phase measurement current transformers, A is an ammeter, and LJ is a current relay, which is connected in series in the current measurement circuit. It can monitor the current size in real time and set the specified value that the circuit is allowed to reach.

[0026] The starting circuit and the self-holding circuit include an automatic starting circuit and a manual starting circuit. The automatic starting circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA1. The manual starting circuit includes an AC contactor KM. The automatic starting circuit and the manual starting circuit are switched by an automatic / manual conversion switch. The self-holding circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA2.

[0027] The fan operation monitoring circuit includes an intermediate relay KA2 and an intermediate relay KA3. The intermediate relay KA3 in the fan operation monitoring circuit is connected in parallel with the AC contactor KM.

[0028] The fan operation indicator light circuit includes the signal light HR and the intermediate relay KA3.

[0029] The power-off delay circuit includes a time relay SJ and an intermediate relay KA1.

[0030] The fan operation circuit in the busbar room includes the fan FJ and the AC contactor KM.

[0031] The fan operation circuit in the circuit breaker room includes the fan FJ and the AC contactor KM.

[0032] The fan operating circuit in the cable room includes the fan FJ and the AC contactor KM.

[0033] Meanwhile, the contents not described in detail in this specification belong to the prior art known to the professional and technical personnel in this field.

[0034] When in use, during normal operation, SA is placed in the automatic gear (1-2 is connected). When the load in the circuit increases and reaches the specified value set by the current relay LJ, its auxiliary contacts are connected, so that the coil of the intermediate relay KA1 in the overcurrent start circuit is energized and closed, and the auxiliary contacts of KA1 in the automatic start circuit are connected, so that the coil of KA2 is energized and closed, and the auxiliary contacts of KA2 in the self-holding circuit and the AC contactor KM circuit are connected respectively. At this time, KA2 can maintain the energized closed state by itself, and at the same time, the coil of the AC contactor KM is energized and closed, and the auxiliary contacts of the AC contactor are all connected, so that the fans FJ installed in various functional rooms (busbar room, circuit breaker room, cable room) in the switch cabinet are all energized and started to run, and the effect of ventilation and heat dissipation can be achieved. At the same time as KA2 is closed, the intermediate relay KA3 connected in parallel to the AC contactor KM is also energized and closed at the same time, so that the signal light HR is lit, and the fan can be monitored to enter the operating state.

[0035] When the load in the circuit is reduced, or the current value drops after heat dissipation and returns to below the specified value set by the current relay LJ, the auxiliary contact of the current relay LJ is disconnected again, causing the intermediate relay KA1 to lose power and disconnect, and its auxiliary contact in series in the power-off delay relay circuit is closed, then the time relay SJ coil is energized, and after the set time is reached, the time relay delay disconnection contact in the automatic start circuit is disconnected, causing the intermediate relay KA2 coil to lose power, thereby disconnecting the auxiliary contact of KA2, and then the AC contactor KM coil loses power and disconnects, and its auxiliary contacts are disconnected at the same time, causing the fans in each functional room to lose power and stop running. When KA2 is disconnected, KA3 is also disconnected and de-energized, and the signal light HR goes out at this time, indicating that the fan has stopped working.

[0036] When maintenance or on-site debugging is required, SA is placed in the stop gear. If necessary, SA is switched to the manual gear (3-4 connected), then the AC contactor KM is connected, each fan FJ starts working, and the signal light HR also lights up. When it is necessary to stop, SA is switched to the stop gear again, each fan stops running, and the signal light HR goes out, realizing manual control.

[0037] In summary, the switch cabinet overload automatic heat dissipation protection circuit is to set exhaust fans in each functional compartment of the power distribution cabinet (such as busbar room, circuit breaker room, cable room), connect a current relay in series in the current measurement circuit, and monitor the load size through this current relay. When the load reaches the specified value set by the current relay, the heat dissipation fan installed in each functional compartment of the switch cabinet can be started for exhaust and heat dissipation. When the current is restored to below the set specified value after exhaust cooling or load reduction, the heat dissipation fan can automatically stop working, and this cycle is repeated to ensure the normal working temperature inside the power distribution cabinet.

[0038] It should be noted that the electrical components appearing in this article are all connected to the external main controller and 220V or 380V mains electricity, and the main controller can be a conventional known device for controlling computers, etc. Its control principle, internal structure and control switch mode are all conventional means of the prior art, which are directly quoted here without further elaboration. In this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A switch cabinet overload automatic heat dissipation protection circuit, characterized in that: It includes an overcurrent starting circuit, which is connected to the power supply through an air switch, and the overcurrent starting circuit includes a current relay LJ and an intermediate relay KA1; Starting circuit and self-holding circuit; The fan operation monitoring circuit includes intermediate relays KA2 and KA3, and the circuit is connected in parallel with the starting circuit; The fan operation indicator light circuit includes the signal light HR and the intermediate relay KA3; Power-off delay circuit, including time relay SJ and intermediate relay KA1; The fan operation circuit in the busbar room includes the fan FJ and the AC contactor KM; The fan operation circuit in the circuit breaker room includes the fan FJ and the AC contactor KM; The fan operating circuit in the cable room includes the fan FJ and the AC contactor KM.

2. The switch cabinet overload automatic heat dissipation protection circuit according to claim 1 is characterized in that: The starting circuit includes an automatic starting circuit and a manual starting circuit. The automatic starting circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA1. The manual starting circuit includes an AC contactor KM. The automatic starting circuit and the manual starting circuit are switched by an automatic / manual conversion switch.

3. The switch cabinet overload automatic heat dissipation protection circuit according to claim 1 is characterized in that: The self-holding circuit includes an intermediate relay KA2, a time relay SJ and an intermediate relay KA2.

4. The switch cabinet overload automatic heat dissipation protection circuit according to claim 2 is characterized in that: The intermediate relay KA3 in the fan operation monitoring circuit is connected in parallel with the AC contactor KM.

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