A kind of localization method of region direct-current ground potential fluctuation sourcesTechnical field
The present invention relates to T & D Technology fields, more particularly, to a kind of positioning of region direct-current ground potential fluctuation sourcesMethod.
Background technique
Nearest is multinomial the study found that magnetic storm, high-altitude nuclear detonation, urban track traffic, DC transmission system monopole the earth fortuneThe activity such as row can cause the obvious fluctuation of a wide range of surface potential, thus on the transformer neutral point of electric system ground connection operationGenerate the very low frequency electric current that DC current is either similar to DC current.This electric current not only jeopardizes the safety fortune of AC networkRow also can generate numerous adverse effects to underground metal pipes and industrial electricity apparatus, not only result in ground potential fluctuation sourcesThe irregular working of electric system and underground metalliferous pipe network system in the neighbourhood, earthquake monitoring stations and networks wrong report, can also generate oneSerial chain reaction, causes great safety accident and economic loss, brings huge negative effect to modern society.
For power transmission network due to its wide geographical distribution and lowohmic network characteristic, ground electric potential fluctuation can be in electric systemCharacteristic current distribution is generated, so power transmission network is the monitoring network that can find ground electric potential fluctuation well.It is limited to meshRelevant transformer neutral point monitoring device is not arranged in preceding electric system for ground electric potential fluctuation, how to go monitoring transformationDevice neutral point current, then carry out the intensity in inverting ground electric potential fluctuation source from current monitoring value and position is a very significant workMake.
It is distributed and carries out for the characteristic current in AC system under the direct current transportation the earth return method of operation both at home and abroad at presentA large amount of research, but these researchs belong to the research of direct ideation, i.e., ground potential is calculated in situation known to fluctuation sourcesFluctuation, to calculate the DC current distribution in electric system.The characteristic morphology electricity of transformer neutral point in known electric systemFlow distribution inverting fluctuation sources parameter (fluctuation sources form, fluctuation sources size of current and fluctuation source position), realizes ground electric potential fluctuation sourceIt positions urgently to be resolved.
Summary of the invention
The present invention provides a kind of localization method of direct-current ground potential fluctuation sources, and this method can realize preliminary criterion fluctuation sources positionIt sets and direction, and calculates position and the size of current in region ground electric potential fluctuation source.
In order to reach above-mentioned technical effect, technical scheme is as follows:
A kind of localization method of region direct-current ground potential fluctuation sources, comprising the following steps:
S1: monitoring region AC network substation grounding neutral point obtains all grounded neutral direct currents of regional power gridFlow size and Orientation；
S2: wave is determined according to the direction of the substation transformer neutral point current of edge placements several in regional exchange power gridThe direction of dynamic ource electric current, and determine fluctuation source region；
S3: the DC current distributed model of AC network is made of node and branch, and combination field road coupling model establishes waveDynamic source and direct current distributed current relationship；
S4: in conjunction with substation's geographical location information, it is randomly provided fluctuation source position and size in fluctuation source region, obtains changeThe distribution of power station neutral point direct current, and compared with measurement result, fluctuation sources size and location is adjusted, until error satisfaction is wantedIt asks.
Further, according to the direction of the substation transformer neutral point current of edge placement and wave in regional exchange power gridThe direction of dynamic ource electric current is identical, chooses the transformer neutral point current direction substation near zone contrary with fluctuation sources and makeesTo fluctuate source region.
Further, the process in the step S3 is:
Enable S=UI, wherein S is conductance matrix, and U is node voltage, and I is node Injection Current:
I.e.
Wherein AgIncidence matrix between node voltage and ground node voltage, GgSubstation grounding conductance matrix；
P=ФgCG+ФdcCdc (3)
Wherein P is surface potential, ФgThe mutual resistance between substation, ФdcThe mutual resistance between substation's fluctuation sources, CgFor substationInjection Current, CdcFor fluctuation sources Injection Current；
Cg=Фg(Ug- P)=Фg(AgU-P) (4)
Simultaneous (2), (3), (4) obtain U:
Wherein K1, K2It is intermediary matrix, formula (5) represents response of the transformer neutral point to interference source.
Further, when error is below 0.1%, fluctuation sources size of current is determined.
Compared with prior art, the beneficial effect of technical solution of the present invention is:
The method of the present invention obtains regional power grid institute according to regional exchange electricity grid substation grounded neutral DC System MonitoringThere is grounded neutral DC current size and Orientation；Consider conducting wire DC impedance, substation grounding resistance, the earth soil resistivityEtc. factors, in conjunction with neutral point current monitoring network, according in the substation transformer of edge placements several in regional exchange power gridProperty point sense of current determines fluctuation sources sense of current, i.e. the neutral point current side of fluctuation sources current direction and edge substationTo identical.If there is the edge substation situation contrary with fluctuation sources, then using the region as fluctuation source region；TrackUnder traffic circulation mode based on existing transformer dc current monitoring data, network DC current parameters and the earth electricity are consideredResistance rate parameter, exploitation ground potential are distributed software for calculation；Then in conjunction with substation's geographical location information, in fluctuation source region machine settingSource position and size are fluctuated, show that substation's neutral point direct current is distributed, and compare with measurement result, adjustment fluctuation sources are bigSmall and position, until error is met the requirements.
Detailed description of the invention
Fig. 1 is the flow chart of this forwarding method.
Specific embodiment
The attached figures are only used for illustrative purposes and cannot be understood as limitating the patent；
In order to better illustrate this embodiment, the certain components of attached drawing have omission, zoom in or out, and do not represent actual productSize；
To those skilled in the art, it is to be understood that certain known features and its explanation, which may be omitted, in attached drawing's.
The following further describes the technical solution of the present invention with reference to the accompanying drawings and examples.
Embodiment 1
As shown in Figure 1, a kind of localization method of region direct-current ground potential fluctuation sources, comprising the following steps:
S1: monitoring region AC network substation grounding neutral point obtains all grounded neutral direct currents of regional power gridFlow size and Orientation；
S2: wave is determined according to the direction of the substation transformer neutral point current of edge placements several in regional exchange power gridThe direction of dynamic ource electric current, and determine fluctuation source region；
S3: the DC current distributed model of AC network is made of node and branch, and combination field road coupling model establishes waveDynamic source and direct current distributed current relationship；
S4: in conjunction with substation's geographical location information, it is randomly provided fluctuation source position and size in fluctuation source region, obtains changeThe distribution of power station neutral point direct current, and compared with measurement result, fluctuation sources size and location is adjusted, until error satisfaction is wantedIt asks.
According to the direction of the substation transformer neutral point current of edge placement in regional exchange power grid and fluctuation ource electric currentDirection it is identical, choose the transformer neutral point current direction substation near zone contrary with fluctuation sources as fluctuation sourcesRegion.
Process in step S3 is:
Enable S=UI, wherein S is conductance matrix, and U is node voltage, and I is node Injection Current:
I.e.
Wherein AgIncidence matrix between node voltage and ground node voltage, GgSubstation grounding conductance matrix；
P=ФgCg+ФdcCdc (3)
Wherein P is surface potential, ФgThe mutual resistance between substation, ФdcThe mutual resistance between substation's fluctuation sources, CgFor substationInjection Current, CdcFor fluctuation sources Injection Current；
Cg=Фg(Ug- P)=Фg(AgU-P) (4)
Simultaneous (2), (3), (4) obtain U:
Wherein K1, K2It is intermediary matrix, formula (5) represents response of the transformer neutral point to interference source.
In ground potential distribution software, electric network model is established, and grid dividing is carried out to it in fluctuation source region；EachGrid element center gradually places fluctuation sources and carries out simulation calculation；Substation's neutral point current value is linearly closed with fluctuation sources current valueSimulation result is become neutral point direct current characteristic value with monitoring and compared by system, determines fluctuation source position；On the basis of above-mentioned stepsOn, increase and decrease simulated current value determines fluctuation sources size of current when error is below 0.1%.
The same or similar label correspond to the same or similar components；
Described in attached drawing positional relationship for only for illustration, should not be understood as the limitation to this patent；
Obviously, the above embodiment of the present invention be only to clearly illustrate example of the present invention, and not be pairThe restriction of embodiments of the present invention.For those of ordinary skill in the art, may be used also on the basis of the above descriptionTo make other variations or changes in different ways.There is no necessity and possibility to exhaust all the enbodiments.It is all thisMade any modifications, equivalent replacements, and improvements etc., should be included in the claims in the present invention within the spirit and principle of inventionProtection scope within.