CN208638025U - A kind of generator neutral point ground connection cabinet - Google Patents

Abstract

A kind of generator neutral point of the utility model is grounded cabinet, including cabinet body and earthing or grounding means, earthing or grounding means is installed in cabinet body, earthing or grounding means includes sequential connection input terminal, disconnecting switch, grounding transformer, secondary current mutual inductor, secondary reactor and secondary resistor, secondary resistor includes mounting rack and multiple wire resistors, wire resistor uniform intervals are installed on mounting rack, and wire resistor includes coiling matrix and resistance wire, the uniform vertical winding of resistance wire is on coiling matrix, and surge layer is formed on coiling matrix, ripple layer surface is coated with inorganic coating layer.The utility model can select different siderochrome aluminum steel or constantan line to be wrapped on coiling matrix as resistance wire according to resistance value difference and form surge layer, increase the heat dissipation area of secondary resistor using surge layer, it can bear higher pulse voltage, it is short to the attack time, but the higher use environment of pulse voltage is adaptable, so that effectively increasing it uses the scope of application.

Description

A kind of generator neutral point ground connection cabinet

Technical field

The utility model relates to technical field of generators, are grounded cabinet more particularly, to a kind of generator neutral point.

Background technique

For a long time, China is substantially all made of isolated neutral mode in 6~35kV electric system, therefore in system Generator neutral point is generally earth-free.The method of operation of isolated neutral have many advantages, such as it is simple, economical, when ground fault Symmetry system having symmetry will not be destroyed, thus a period of time that can operate with failure, but ground fault resonance overvoltage may occur With intermittent arc grounding overvoltage, above-mentioned ground-fault over-voltages multiple is high, spreads whole system, poor to system interior insulation Equipment especially alternating current generator be a serious threat.

With the continuous improvement of China's electric system cable degree, capacitance current is continuously increased in system, is grounded The harmfulness of failure resonance overvoltage and intermittent arc grounding fault overvoltage is increasingly severe.Past, to prevent ground connection event Hinder the harm of overvoltage, only accesses metal zinc oxide lightning arrester in generator neutral point, the safety of this protection and reliable Property is not enough.

Currently, in order to effectively inhibit ground-fault over-voltages, generator neutral point uses neutral point to pass through more and more The mode of resistance eutral grounding accesses the grounding resistor of certain resistance value, above-mentioned ground connection electricity that is, between generator neutral point and the earth A manual switch, above-mentioned generator neutral point, manual switch, ground resistance are electrically connected between resistance device and generator neutral point Device and the earth constitute a circuit.

When occurring the failures such as single-phase earthing in electricity generation system, above-mentioned grounding resistor can effectively inhibit intermittent arc Light grounding surge, after ground arc extinguishes, the residual charge in system direct-to-ground capacitance will be released by neutral resistor, Therefore very high overvoltage will not be generated；Meanwhile AC generator neutral point resistance grounded can also eliminate system earth event Hindering resonance overvoltage, neutral resistor is equivalent to the system direct-to-ground capacitance both ends in resonant tank and connects a damping resistance, Due to the damping action of resistance, the various resonance overvoltages of system can be substantially eliminated, effectively limit earth-fault current pair The damage of alternating current generator.

However, the generator neutral point ground connection cabinet that China produces at present uses the longevity due to resistor in use The problem of life, causes generator neutral point ground connection cabinet needs to be regularly maintained, seriously affects its utilization rate, and increase to staff Workload.

Utility model content

The utility model provides a kind of simple structure, long service life and generator neutral point ground connection cabinet convenient for safeguarding, To solve the upper existing generator neutral point ground connection technical problem that cabinet service life is short, maintenance cost is high.

One aspect according to the present utility model provides a kind of generator neutral point ground connection cabinet, including cabinet body and ground connection dress It sets, the cabinet body includes frame and shell, and the shell is coated on the outling of truss into a cavity, the earthing or grounding means installing In the cavity, the earthing or grounding means includes that sequential connection input terminal, disconnecting switch, grounding transformer, secondary current are mutual Sensor, secondary reactor and secondary resistor, the secondary resistor include mounting rack and multiple wire resistors, the coiling electricity Resistance uniform intervals are installed on the mounting rack, and the wire resistor includes coiling matrix and resistance wire, and the resistance wire is equal Even vertical winding forms surge layer on the coiling matrix on the coiling matrix, and the ripple layer surface is coated with Inorganic coating layer.

On the basis of above scheme preferably, the resistance wire is wrapped in the coiling matrix by the way of reversed double winding On.

On the basis of above scheme preferably, the coiling matrix is high temperature resistant mullite porcelain tube.

On the basis of above scheme preferably, the resistance wire is one of constantan line and Fe-Cr-Al wire.

On the basis of above scheme preferably, the grounding transformer be equipped with a head end terminal, a tail end terminal and Two secondary terminals, a head end terminal are connected with the output end of the disconnecting switch, a tail end terminal and peace Dress primary current mutual inductor on the housing is connected, the secondary terminals respectively with the secondary current mutual inductor and described Secondary resistor is electrical connected.

On the basis of above scheme preferably, the grounding transformer is dry type epoxy cast transformer.

On the basis of above scheme preferably, the outer upper part on the shell is equipped with multiple air-vents, and the air-vent is equal Even laying, and the air-vent and the shell are in 35~45 °.

On the basis of above scheme preferably, the top of the cabinet body is equipped with weather shield, and is installed on the weather shield Air-introduced machine, the air outlet of the air-introduced machine are linearly arranged with the air-vent.

A kind of generator neutral point of the utility model is grounded cabinet, using high temperature resistant mullite porcelain tube as coiling matrix, And it selects different siderochrome aluminum steel or constantan line to be wrapped on coiling matrix as resistance wire according to resistance value difference and forms ripple Layer, is increased the heat dissipation area of secondary resistor using surge layer, can bear higher pulse voltage, short to the attack time, But the higher use environment of pulse voltage is adaptable, so that effectively increasing it uses the scope of application.

Meanwhile resistance wire is also wrapped on coiling matrix to form surge layer by the utility model, and in ripple layer surface Coating inorganic dope layer, using inorganic coating can further effective protection resistance wire it is not oxidized, prolong its service life, mention Its high service life, to reduce its maintenance cost.

Detailed description of the invention

Fig. 1 is that a kind of generator neutral point of the utility model is grounded the structure chart of cabinet；

Fig. 2 is the structure chart of the wire resistor of the utility model.

Specific embodiment

With reference to the accompanying drawings and examples, specific embodiment of the present utility model is described in further detail.Below Embodiment is not intended to limit the scope of the present invention for illustrating the utility model.

Referring to Fig. 1, simultaneously as shown in connection with fig. 2, the utility model provides a kind of generator neutral point ground connection cabinet, including cabinet Body 50 and earthing or grounding means.

Wherein, cabinet body 50 includes frame and shell, and shell is coated on outling of truss into a cavity, and earthing or grounding means is installed in chamber In vivo, earthing or grounding means include sequential connection input terminal 1, it is disconnecting switch 2, grounding transformer 3, secondary current mutual inductor 7, secondary Reactor 8 and secondary resistor 9,

Secondary resistor 9 includes mounting rack and multiple wire resistors 20, and 20 uniform intervals of wire resistor are installed in mounting rack On, and wire resistor 20 include coiling matrix 21 and resistance wire 22, the uniform vertical winding of resistance wire 22 on coiling matrix 21, and Surge layer is formed on coiling matrix 21, ripple layer surface is coated with inorganic coating layer.

In use process, it is connected using input terminal 1 with generator neutral point, passes through secondary reactor 8 and secondary resistance Device 9 is parallel-connected to the secondary side of grounding transformer 3, using the impedance mapping function of transformer, is allowed to conversion to ground connection transformation 3 primary side of device, is equivalent to high induction reactance.Grounding transformer 3 is once flanked between generator neutral point and ground, high sense is become Anti- earthing or grounding means.The present apparatus selects suitable secondary reactor 8 and secondary resistor 9, can reach the large-scale hydroelectric generator of limitation It, will under conditions of meeting generator neutral point displacement voltage no more than 10% specified phase voltage when there is singlephase earth fault Current in the fault point is limited in the purpose within 15A.High grounding still can be used in the configuration of one-phase ground protection simultaneously, Select instantaneous tripping.The risk that thus can effectively reduce generator stator core scaling loss using the present apparatus improves generator fortune Capable reliability.

It is worth noting that the structure that the utility model also uses mounting rack to combine with multiple wire resistors 20 forms two Secondary resistor 9, cooperation resistance wire 22 form surge layer on 21 surface of coiling matrix, improve its surface radiating effect, effectively lower Parasitic inductor, and using high temperature resistant, the fire-retardant and inorganic coating that insulate, it is not oxidized to be effectively ensured resistance wire 22, effectively prolongs Its long service life.

In another preferred embodiment of the utility model, the resistance wire 22 of the utility model uses the side of reversed double winding Formula is wrapped on coiling matrix 21, can produce noninductive wire resistor 20, and parasitic inductance can be reduced further, thus with into One step improves its service life.

It is worth noting that the coiling matrix 21 of the utility model is high temperature resistant mullite porcelain tube, and according to resistance value Difference can select one of constantan line and Fe-Cr-Al wire to be used as resistance wire 22.

Please continue to refer to shown in Fig. 1, the grounding transformer 3 of the utility model is equipped with 4, tail ends of a head end terminal Terminal 5 and two secondary terminals 11, one time head end terminal 4 is connected with the output end of disconnecting switch 2, a tail end terminal 5 and peace Primary current mutual inductor on shell is connected, and secondary terminals 11 are electric with secondary current mutual inductor 7 and secondary resistor 9 respectively Property be connected.

Wherein, grounding transformer 3 be dry type epoxy cast transformer, and its rated capacity be short-circuit impedance percentage≤ 3%, total equivalent loss≤1.5%.

Heat dissipation effect in cabinet body 50 in order to guarantee the utility model, outer upper part of the utility model also on shell are set There are multiple air-vents, air-vent is uniformly distributed, and air-vent and shell are in 35~45 °, utilize the angle between air-vent and shell Degree, effectively can inwardly pour into extraneous cold wind, and make cold wind middle and lower part migration into cabinet, to guarantee its good heat dissipation Property.

Preferably, the utility model is also equipped with weather shield at the top of cabinet body 50, and air-introduced machine is installed on weather shield, The air outlet of air-introduced machine is linearly arranged with air-vent.It, can effectively really using the relative positional relationship of air-introduced machine and air-vent It protects the air quantity that air-introduced machine generates inwardly to export, guarantees its cooling effect.

A kind of generator neutral point of the utility model is grounded cabinet, using high temperature resistant mullite porcelain tube as coiling matrix 21, and select different siderochrome aluminum steel or constantan line to be wrapped in shape on coiling matrix 21 as resistance wire 22 according to resistance value difference Corrugated layer is increased the heat dissipation area of secondary resistor 9 using surge layer, higher pulse voltage can be born, to impact Time is short, but the higher use environment of pulse voltage is adaptable, so that effectively increasing it uses the scope of application.

Meanwhile resistance wire 22 is also wrapped in form surge layer on coiling matrix 21 by the utility model, and in surge layer Surface coating inorganic dope layer, using inorganic coating can further effective protection resistance wire 22 it is not oxidized, extend its use Service life improves its service life, to reduce its maintenance cost.

Finally, the present processes are only preferable embodiment, it is not intended to limit the protection scope of the utility model. Within the spirit and principle of the utility model, any modification, equivalent replacement, improvement and so on should be included in this reality Within novel protection scope.

Claims (8)

1. a kind of generator neutral point is grounded cabinet, which is characterized in that including cabinet body and earthing or grounding means, the cabinet body include frame and Shell, the shell are coated on the outling of truss into a cavity, and the earthing or grounding means is installed in the cavity, the ground connection Device includes sequential connection input terminal, disconnecting switch, grounding transformer, secondary current mutual inductor, secondary reactor and secondary Resistor, the secondary resistor include mounting rack and multiple wire resistors, and the wire resistor uniform intervals are installed in described On mounting rack, and the wire resistor includes coiling matrix and resistance wire, and the uniform vertical winding of resistance wire is in the coiling On matrix, and surge layer is formed on the coiling matrix, the ripple layer surface is coated with inorganic coating layer.

2. a kind of generator neutral point as described in claim 1 is grounded cabinet, which is characterized in that the resistance wire is using reversed double The mode of coiling is wrapped on the coiling matrix.

3. a kind of generator neutral point as described in claim 1 is grounded cabinet, which is characterized in that the coiling matrix is high temperature resistant Mullite porcelain tube.

4. a kind of generator neutral point as described in claim 1 is grounded cabinet, which is characterized in that the resistance wire be constantan line and One of Fe-Cr-Al wire.

5. a kind of generator neutral point as described in claim 1 is grounded cabinet, which is characterized in that the grounding transformer is equipped with Head end terminal, a tail end terminal and two secondary terminals, the output of a head end terminal and the disconnecting switch End is connected, and a tail end terminal is connected with the primary current mutual inductor of installation on the housing, the secondary terminals point It is not electrical connected with the secondary current mutual inductor and the secondary resistor.

6. a kind of generator neutral point as claimed in claim 5 is grounded cabinet, which is characterized in that the grounding transformer is dry type Epoxy cast transformer.

7. a kind of generator neutral point as described in claim 1 is grounded cabinet, which is characterized in that the outer upper part on the shell Equipped with multiple air-vents, the air-vent is uniformly distributed, and the air-vent and the shell are in 35~45 °.

8. a kind of generator neutral point as claimed in claim 7 is grounded cabinet, which is characterized in that the top of the cabinet body is equipped with gear Rain plate, and air-introduced machine is installed on the weather shield, the air outlet of the air-introduced machine is linearly arranged with the air-vent.