A kind of transformer neutral point resistance-type presses down straight device grounding system
Technical field
The transformer neutral point resistance-type that relates to the utility model presses down straight device grounding system, particularly transformer neutral point DC current and the monitoring of alternating current and the improvement of transformer DC magnetic bias.
Background technology
When HVDC (High Voltage Direct Current) transmission system is run in one pole the earth mode, near direct current grounding pole, just there is direct current to flow in AC transformer through directly grounded neutral point from ground, cause transformer DC magnetic bias problem.Transformer neutral point resistance-type presses down straight device and is formed in parallel by resistor, mechanical bypass switch and fast bypass-loop, is connected between transformer neutral point and ground.When not having direct current to flow through transformer neutral point, mechanical bypass switch is closed position.When detecting that the direct current flowing through transformer neutral point exceedes limit value, mechanical bypass switch transfers open position to, and resistor is dropped into, and plays the effect preventing direct current.
Resistance-type needs out of service when pressing down straight turnaround of unit, at this moment transformer neutral point also needs reliable ground, grid company also will monitor transformer neutral point DC current and alternating current, therefore design grounding system is needed, not only transformer DC magnetic bias can be administered, and resistance-type press down straight turnaround of unit out of service time, grid company can monitor transformer neutral point DC current and alternating current.
Utility model content
The purpose of this utility model is the shortcoming overcoming above-mentioned prior art, provides a kind of transformer neutral point resistance-type to press down straight device grounding system.
For solving the problem, the technical solution adopted in the utility model is:
A kind of transformer neutral point resistance-type presses down straight device grounding system, comprises transformer neutral point, resistance-type presses down straight device, earthing switch blade, presses down straight plug-in strip, earth electrode and distant place measurement and control unit,
Described resistance-type presses down straight device and comprises resistor, mechanical bypass switch, thyristor valve, reactor, grounding copper bar, inlet wire copper bar, AC current transformer and DC current transformer;
Described thyristor valve and reactor are composed in series quick bypass circuit, and thyristor valve is made up of diode rectifier bridge and thyristor;
After described resistor, quick bypass circuit and mechanical bypass switch parallel connection, one end connects grounding copper bar, and the other end connects inlet wire copper bar; Described DC current transformer and AC current transformer are set on grounding copper bar;
Described resistor group is for suppressing the direct current flowing through transformer neutral point;
Described mechanical bypass switch is used for dropping into, excising resistor;
Described quick bypass circuit is used for excising resistor fast;
Described DC current transformer is for gathering the direct current of transformer neutral point;
Described AC current transformer is for gathering the alternating current of transformer neutral point;
Described transformer neutral point and earthing switch blade and the high-pressure side pressing down straight plug-in strip are connected; Earthing switch blade low-pressure side is connected with the grounding copper bar that resistance-type presses down in straight device by a cable, presses down straight plug-in strip low-pressure side and is connected with the inlet wire copper bar that resistance-type presses down in straight device by a cable; Grounding copper bar is connected to earth electrode by metallic conductor; The DC current signal of DC current transformer collection and the ac current signal of AC current transformer collection are sent to distant place measurement and control unit by secondary cable, and distant place measurement and control unit is by the power system monitoring net of electric power system specialized protocol access grid company.
In order to better realize the utility model, described resistance-type presses down straight device and also comprises discharging gap, and discharging gap is in parallel with resistor, fast bypass circuit and mechanical bypass switch, for the backup protection as resistor.
In order to better realize the utility model, described thyristor anode is connected with the DC side positive pole of diode rectifier bridge, thyristor negative electrode is connected with the DC side negative pole of diode rectifier bridge, one end of reactor is connected with AC one end of diode rectifier bridge, the other end of reactor is connected with inlet wire bronze medal, and the AC other end of diode rectifier bridge is connected with ground connection bronze medal.
In order to better realize the utility model, described thyristor anode is connected with the DC side positive pole of diode rectifier bridge, thyristor negative electrode is connected with the DC side negative pole of diode rectifier bridge by reactor, AC one end of diode rectifier bridge is connected with inlet wire bronze medal, and the other end is connected with ground connection bronze medal.
This system resistance-type press down straight device drop into, out of service time, all there is the function of administering D.C. magnetic biasing, direct current and the alternating current of transformer neutral point can be monitored in addition, guarantee to press down straight device under normal operation and maintenance situation in resistance-type, the power system monitoring net of grid company can both monitor direct current and the alternating current of transformer neutral point simultaneously.
When the resistance-type that is used for earthing switch blade presses down straight device stoppage in transit maintenance, close a floodgate and make transformer neutral point reliable metal ground connection; Press down directly cutter to be used for resistance-type and to press down straight device when normally running, close a floodgate and make transformer press down straight device ground connection by resistance-type; Power system monitoring net can the signal of the DC current transformer that detects of monitoring record measurement and control unit and AC current transformer.
Compared with prior art, tool has the following advantages and beneficial effect the utility model:
This grounding system presses down straight device in resistance-type and normally runs and in maintenance situation, can both realize D.C. magnetic biasing and administer and direct current, monitoring alternating current function, and scheme be simple and reliable, easy to maintenance, is suitable for applying.
Accompanying drawing explanation
Fig. 1 is the theory diagram that described in the utility model embodiment 1, a kind of transformer neutral point resistance-type presses down straight device grounding system;
Fig. 2 is the theory diagram that described in the utility model embodiment 2, a kind of transformer neutral point resistance-type presses down straight device grounding system.
Embodiment
Below in conjunction with embodiment and accompanying drawing, execution mode of the present utility model is described in further detail, but execution mode of the present utility model is not limited thereto.
Embodiment 1
As shown in Figure 1, a kind of transformer neutral point resistance-type presses down straight device grounding system, comprise transformer neutral point 1, resistance-type press down straight device 2, earthing switch blade 3, press down straight plug-in strip 4, earth electrode 5 and distant place measurement and control unit 6,
Described resistance-type presses down straight device 2 and comprises resistor 7, mechanical bypass switch 8, thyristor valve 9, reactor 10, grounding copper bar 11, inlet wire copper bar 12, AC current transformer 13 and DC current transformer 14;
Described thyristor valve 9 is composed in series quick bypass circuit with reactor 10, and thyristor valve 9 is made up of diode rectifier bridge 15 and thyristor 16;
Described resistor 7, fast bypass circuit and mechanical bypass switch 8 rear one end in parallel connect grounding copper bar 11, and the other end connects inlet wire copper bar 12; Described DC current transformer 14 and AC current transformer 13 are set on grounding copper bar 11;
Described resistor 7 groups is for suppressing the direct current flowing through transformer neutral point 1;
Described mechanical bypass switch 8 is for dropping into, excising resistor 7;
Described quick bypass circuit is used for excision resistor 7 fast;
Described DC current transformer 14 is for gathering the direct current of transformer neutral point 1;
Described AC current transformer 13 is for gathering the alternating current of transformer neutral point 1;
Described transformer neutral point 1 and earthing switch blade 3 and the high-pressure side pressing down straight plug-in strip 4 are connected; Earthing switch blade 3 low-pressure side is connected with the grounding copper bar 11 that resistance-type presses down in straight device 2 by a cable 18, presses down straight plug-in strip 4 low-pressure side and is connected with the inlet wire copper bar 12 that resistance-type presses down in straight device by a cable 18; Grounding copper bar 11 is connected to earth electrode 5 by metallic conductor; The DC current signal that DC current transformer 14 gathers and the ac current signal that AC current transformer 13 gathers are sent to distant place measurement and control unit 6 by secondary cable 19, and distant place measurement and control unit 6 is by the power system monitoring net of electric power system specialized protocol access grid company.
In order to better realize the utility model, described resistance-type presses down straight device 2 and also comprises discharging gap 17, and discharging gap 17 is in parallel with resistor 7, fast bypass circuit and mechanical bypass switch 8, for the backup protection as resistor 7.
In order to better realize the utility model, described thyristor 16 anode is connected with the DC side positive pole of diode rectifier bridge 15, thyristor 16 negative electrode is connected with the DC side negative pole of diode rectifier bridge 15, one end of reactor 10 is connected with AC one end of diode rectifier bridge 15, the other end of reactor 10 is connected with inlet wire bronze medal 12, and the AC other end of diode rectifier bridge 15 is connected with ground connection bronze medal 11.
In order to better realize the utility model, described thyristor 16 anode is connected with the DC side positive pole of diode rectifier bridge 15, thyristor 16 negative electrode is connected with the DC side negative pole of diode rectifier bridge 15 by reactor 10, AC one end of diode rectifier bridge 15 is connected with inlet wire bronze medal 12, and the other end is connected with ground connection bronze medal 11.
Embodiment 2
As shown in Figure 2, described thyristor 16 anode is connected with the DC side positive pole of diode rectifier bridge 15, thyristor 16 negative electrode is connected with the DC side negative pole of diode rectifier bridge 15 by reactor 10, AC one end of diode rectifier bridge 15 is connected with inlet wire bronze medal 12, the other end is connected with ground connection bronze medal 11, and all the other are with embodiment 1.
This system resistance-type press down straight device 2 drop into, out of service time, all there is the function of administering D.C. magnetic biasing, direct current and the alternating current of transformer neutral point can be monitored in addition, guarantee that the power system monitoring net of grid company can both monitor direct current and the alternating current of transformer neutral point simultaneously under resistance-type presses down the normal operation of straight device 2 and maintenance situation.
Transformer neutral point grounding system resistance-type press down straight device 2 normally run time, press down straight plug-in strip 4 to close a floodgate, earthing switch blade 3 separating brake, transformer neutral point 1 presses down straight device 2 ground connection by resistance-type, realizes D.C. magnetic biasing abatement functions and direct current, monitoring alternating current function.When resistance-type presses down straight device 2 stoppage in transit maintenance, earthing switch blade 3 closes a floodgate, press down straight plug-in strip 4 separating brake, to be pressed down the grounding copper bar 11 in straight device 2 by cable 18 contact resistance formula due to earthing switch blade 3, grounding copper bar 11 accesses earth mat by metallic conductor, and DC current transformer 14, AC current transformer 13 are embedded on grounding copper bar 11, realizes transformer neutral point 1 directly ground connection, resistance-type presses down straight device 2 and can overhaul, and direct current, alternating current also can be monitored simultaneously.