CN206832927U - A kind of Little Current Ground Connection System - Google Patents
A kind of Little Current Ground Connection System Download PDFInfo
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- CN206832927U CN206832927U CN201720483305.1U CN201720483305U CN206832927U CN 206832927 U CN206832927 U CN 206832927U CN 201720483305 U CN201720483305 U CN 201720483305U CN 206832927 U CN206832927 U CN 206832927U
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Abstract
A kind of Little Current Ground Connection System, including high-frenquency current blocking device, bandpass filter, high-frequency signal source, high-frequency signal protective relaying device, the wire selection system is arranged in the outlet being electrically connected with three phase mains bus, the outlet includes three-phase outlet, respectively A phases outlet, B phase outlets, C phase outlets, the high-frenquency current blocking device is arranged in every phase outlet between three phase mains bus, and set one per phase outlet head and the tail are each, between two high-frenquency current blocking devices, it is connected per phase outlet by bandpass filter with high-frequency signal protective relaying device, and, also it is connected per phase outlet by bandpass filter with high-frequency signal source.The advantages of system and the determination methods using the system, is：Which bar ground connection in the outlet between three phase mains bus can be rapidly judged.
Description
Technical field
It the utility model is related to electric power network technique field, more particularly to a kind of Little Current Ground Connection System.
Background technology
When single-phase earthing occurs in neutral nondirect earthing network (also known as small current neutral grounding system), due to trouble point
Electric current very little, and the line voltage between three-phase remains in that symmetrically, and the power supply on load does not influence, therefore, general
In the case of all allow to be further continued for operation 1 to 2 hour, without tripping immediately, this is also to be run using neutral point indirect earthing
Major advantage.But after single-phase earthing, the voltage-to-ground of other two-phases will raiseTimes.In order to prevent failure from entering one
Step is expanded into or multipoint earthing short circuit at 2 points, signal should be just sent in time, so that operations staff takes measures to be eliminated.
Therefore, in single-phase earthing, typically only require that relay protection can selectively send signal, without tripping.
But when single-phase earthing is dangerous to the safety of the person and equipment, then it should act in tripping operation.
Regrettably, when single-phase earthing occurring in neutral point non-direct grounding system, zero-sequence current is very small, accurately selects
Failure outlet is always a problem of scientific research personnel's exploratory development.
Utility model content
The purpose of this utility model is to solve not judging in the prior art going out between three phase mains bus
The problem of which bar outlet is grounded in line, provides a kind of Little Current Ground Connection System herein.
To achieve the above object, the technical solution adopted in the utility model is as follows：
A kind of Little Current Ground Connection System, including high-frenquency current blocking device, bandpass filter, high-frequency signal source, high-frequency signal
Protective relaying device, the wire selection system are arranged in the outlet being electrically connected with three phase mains bus, and the outlet includes three
Phase outlet, the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device are arranged on every between three phase mains bus
In phase outlet, and per phase outlet, head and the tail are each sets one, between two high-frenquency current blocking devices, per phase outlet by bandpass filter with
High-frequency signal protective relaying device connects, also, is also connected per phase outlet by bandpass filter with high-frequency signal source.
Further, the neutral ground connection of the high-frequency signal source.
Further, the high-frequency signal protective relaying device is microcomputer type high-frequency signal protective relaying device.
Further, in addition to time lagged type protective relaying device, the time lagged type protective relaying device are arranged on band logical filter
Between ripple device and high-frequency signal source.
Further, when outlet is a plurality of, multiple wire selection systems share a high-frequency signal protective relaying device.
Further, every group of high-frequency signal source produces the symmetrical, high-frequency signal of three-phase, and each high-frequency signal source production
The frequency of raw high-frequency signal differs, and the high-frenquency current blocking device in every outlet produces this outlet high frequency signal source
Raw high frequency electric is limited in the outlet between two high-frenquency current blocking devices.
Further, the bandpass filter filters out power current.
It is as follows using the determination methods of above-mentioned Little Current Ground Connection System, step：
(1) system is connected first and completed；
(2) system is worked, and the HF signal generator produces high frequency electric, and the high-frequency signal protective relaying device is born
Duty receives the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device during non-zero-sequence current, judge
The equal normal operation of line；When high-frequency signal protective relaying device detects high frequency zero-sequence current, comprehensive analysis each group high-frequency signal
The frequency and amplitude of high-frequency signal frequency caused by source and the zero-sequence current, any bar outlet ground connection judged.
The beneficial effect of the utility model is：
(1) the utility model can accurately judge which bar outlet ground connection in the outlet between three phase mains bus.
(2) very big impedance is presented to the high frequency electric in this outlet for the high-frenquency current blocking device in the utility model, to power frequency
Low ESR is presented in electric current, and the position of high-frenquency current blocking device and the setting of number are limited in high frequency electric in this outlet, and power frequency
Electric current can pass through, so as to not influence the transmission of electric energy.
(3) Low ESR is presented to the high frequency electric needed for this outlet in the setting of bandpass filter in the utility model, from
Outlet and high frequency electric are output into microcomputer type high-frequency signal relay protection dress from high-frequency signal source without influenceing high frequency electric
In putting, high impedance is presented to power current, prevents that power current from entering high-frequency signal source and microcomputer type high-frequency signal relay is protected
In protection unit, and damage high-frequency signal source and microcomputer type high-frequency signal protective relaying device.
(4) time lagged type protective relaying device is responsible for protecting high-frequency signal source in the utility model, when outlet high-frequency current
During more than setting value, the delay tripping of time lagged type protective relaying device, the action of protection high-frequency signal source is played.
Brief description of the drawings
Fig. 1 is a kind of Little Current Ground Connection System of the present utility model and the basic circuit diagram of determination methods；
Fig. 2 is the circuit of a kind of Little Current Ground Connection System of the present utility model and the specific embodiment of determination methods
Figure.
Embodiment
As shown in figure 1, a kind of Little Current Ground Connection System, including high-frenquency current blocking device 1, bandpass filter 2, high-frequency signal
Source 3, high-frequency signal protective relaying device 4, time lagged type protective relaying device 5, the neutral-point solid ground of high-frequency signal source 3.It is high
Frequency signal protective relaying device 4 is microcomputer type high-frequency signal protective relaying device 4.Bandpass filter 2 prevents power current from entering
In high-frequency signal source and microcomputer type high frequency protective relaying device.
The wire selection system is arranged in the outlet being electrically connected with three phase mains bus, and the outlet goes out including three-phase
Line, the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device 1 are arranged on every phase between three phase mains bus
In outlet, and one is set per phase outlet head and the tail are each, between two high-frenquency current blocking devices 1, pass through bandpass filter 2 per phase outlet
It is connected with microcomputer type high-frequency signal protective relaying device 4, also, also passes through bandpass filter 2 and high-frequency signal source 3 per phase outlet
Connection, time lagged type protective relaying device 5 are arranged between bandpass filter 2 and high-frequency signal source 3.High-frenquency current blocking device 1 is to originally going out
Very big impedance is presented in high frequency electric in line, and Low ESR, the position of high-frenquency current blocking device 1 and setting for number is presented to power current
Put and high frequency electric is limited in this group of outlet, and power current can pass through, so as to not influence the transmission of electric energy.
When outlet for it is a plurality of when, multiple wire selection systems share a high-frequency signal protective relaying device 4 or each
High-frequency signal protective relaying device 4 in wire selection system mutual transmission signal in a communication manner.
Determination methods are as follows：
(1) system is connected first and completed；
(2) system works, and the HF signal generator 3 produces high frequency electric, the high-frequency signal protective relaying device 4
It is responsible for receiving the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device 4 during non-zero-sequence current, sentence
The equal normal operation of disconnected outlet；When high-frequency signal protective relaying device 4 detects high frequency zero-sequence current, comprehensive analysis each group high frequency
The frequency and amplitude of high-frequency signal frequency caused by signal source 4 and the zero-sequence current, any bar outlet ground connection judged.
Specific implementation is as follows：
Assuming that outlet is three, the wire selection system of three outlets shares a high-frequency signal protective relaying device 4.Often
The frequency that group high-frequency signal source 3 produces high-frequency signal caused by the symmetrical, high-frequency signal of three-phase and three groups of high-frequency signal sources 3 is equal
Differ, high frequency electric caused by this outlet high frequency signal source is limited in two by the high-frenquency current blocking device in every outlet
In outlet between individual high-frenquency current blocking device.
It is specific as follows：
As shown in Fig. 2 three outlets are respectively L1, L2, L3, three outlets are produced by respective high-frequency signal source 3
Symmetrically, the high-frequency signal of three-phase, and the high-frequency signal frequency of three outlets differs, it is assumed that outlet L1 in this system
The frequency of high-frequency signal caused by high-frequency signal source 3 is 10MHz, the frequency of high-frequency signal caused by outlet L2 high-frequency signal source 3
Rate is 11MHz, and the frequency of high-frequency signal caused by outlet L3 high-frequency signal source 3 is 12MHz, the three-phase high-frequency electrical of three outlets
Stream is linked into microcomputer type high-frequency signal protective relaying device 4.Due to the presence of each bar outlet medium-high frequency trap 1 so that
High frequency electric caused by each group outlet high frequency signal source 3 can not flow into other outlets, that is to say, that be flowed through in outlet L1
Electric current only has the electric current of two kinds of frequencies of 50Hz and 10MHz, and the electric current flowed through in outlet L2 only has two kinds of frequencies of 50Hz and 11MHz
Electric current, the electric current flowed through in outlet L3 only have the electric current of two kinds of frequencies of 50Hz and 12MHz.Meanwhile and due to bandpass filter 2
Presence so that power current cannot be introduced into microcomputer type high-frequency signal protective relaying device 4, then, outlet L1 flow into microcomputer
The power frequency of type high-frequency signal protective relaying device 4 can only be 10MHz, and outlet L2 flows into microcomputer type high-frequency signal relay protection
The power frequency of device 4 can only be 11MHz, and outlet L3 flows into the power frequency of microcomputer type high-frequency signal protective relaying device 4 only
Can be 12MHz.
Usually each outlet is in normal operation, because outlet L1, outlet L2 and outlet L3 are without generation earth fault, institute
There is no zero-sequence current in microcomputer type high-frequency signal protective relaying device 4.It is assumed that single-phase earthing occurs for the C phases that some time carves line L3
Failure, now, the zero-sequence current of power frequency will be produced in outlet L3, this electric current is the small electricity in isolated neutral system
Stream, numerical value very little, will not damage transmission of electricity outlet；Also the zero-sequence current that frequency is 12MHz can be produced in outlet L3, this electric current is
As caused by outlet L3 high-frequency signal source 3, because this high-frequency signal source 3 is neutral ground, so current values are very
Greatly (" very big " be for former high frequency electric, for the power current in outlet L3, this high frequency electric
Numerical value or very little, transmission of electricity outlet will not be damaged)；Power frequency zero-sequence current can flow into other outlets, still, frequency 12MHz
Zero-sequence current can only be flowed through on outlet L3.That is, if microcomputer type high-frequency signal protective relaying device 4 detects and is
The zero-sequence current for having frequency to be 12MHz in system flows through, and is only likely to be and occurs on outlet L3 caused by earth fault.And this
When, the high frequency electric for flowing into microcomputer type high-frequency signal protective relaying device 4 is：Outlet L3 flows into the three-phase electricity that frequency is 12MHz
Stream, by the calculating of microcomputer type high-frequency signal protective relaying device 4, there is a zero-sequence current that frequency is 12MHz, and numerical value is very big；Go out
Line L1 flows into the three-phase current that frequency is 10MHz, by the calculating of microcomputer type high-frequency signal protective relaying device 4, has the frequency to be
10MHz zero-sequence current, but numerical value is much smaller than the high frequency electric that frequency is 12MHz；It is 11MHz's that outlet L2, which flows into frequency,
Three-phase current, by the calculating of microcomputer type high-frequency signal protective relaying device 4, there is the zero-sequence current that frequency is 11MHz, but count
Value is much smaller than the high frequency electric that frequency is 12MHz.So, the can of microcomputer type high-frequency signal protective relaying device 4 is according to zero sequence
The frequency and numerical values recited of electric current, it is that there occurs earth fault by outlet L3 to determine.
Specifically, if outlet L3 generations are not singlephase earth faults, but line to line fault is grounded, now, microcomputer type
High-frequency signal protective relaying device 4 also has the inflow of high frequency zero-sequence current, but line to line fault ground connection belongs to phase fault,
Can easily it be judged with device by other Principles of Relay Protections, such as three-step charging, it can so distinguish
Whether singlephase earth fault is belonged to.
Further, time lagged type protective relaying device 5 is arranged between high-frequency signal source 3 and bandpass filter 2, when this
When outlet high-frequency current is more than setting value, time lagged type protective relaying device 5 is delayed t ability trippings after default duration, plays guarantor
The effect of high-frequency signal source 3 is protected, delay t is set greater than microcomputer type high-frequency signal protective relaying device 4 to single-phase earthing occurs
Time for making a choice of outlet, so in default duration, microcomputer type high-frequency signal protective relaying device 4 has collected
The electric current of each bar outlet different frequency, calculates the size of each frequency zero-sequence current, so not influenceing the work of line selection apparatus.
Determination methods are as follows：
(1) system is connected first and completed；
(2) system works, and the HF signal generator 3 produces high frequency electric, the high-frequency signal protective relaying device
It is responsible for receiving the high frequency electric passed back from transmission of electricity outlet；Among high-frequency signal protective relaying device during non-zero-sequence current, judge
The equal normal operation of outlet；When high-frequency signal protective relaying device detects high frequency zero-sequence current, comprehensive analysis each group high frequency letter
The frequency and amplitude of number high-frequency signal frequency caused by source and the zero-sequence current, any bar outlet ground connection judged.
The preferred embodiment that the utility model is created is these are only, is not created to limit the utility model, it is all
All any modification, equivalent and improvement made within the spirit and principle that the utility model is created etc., should be included in this
Within the protection domain that utility model is created.
Claims (7)
- A kind of 1. Little Current Ground Connection System, it is characterised in that including high-frenquency current blocking device, bandpass filter, high-frequency signal source, High-frequency signal protective relaying device, the wire selection system be arranged on three phase mains bus be electrically connected with outlet on, it is described go out Line includes three-phase outlet, and the respectively outlet of A phases, the outlet of B phases, C phase outlets, the high-frenquency current blocking device is arranged on three phase mains bus Between every phase outlet on, and per phase outlet, head and the tail are each sets one, between two high-frenquency current blocking devices, pass through band logical per phase outlet Wave filter is connected with high-frequency signal protective relaying device, also, is also connected per phase outlet by bandpass filter and high-frequency signal source Connect.
- 2. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that in the high-frequency signal source Property point grounding connection.
- 3. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that the high-frequency signal relay is protected Protection unit is microcomputer type high-frequency signal protective relaying device.
- 4. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that also protected including time lagged type relay Protection unit, the time lagged type protective relaying device are arranged between bandpass filter and high-frequency signal source.
- 5. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that more when outlet is a plurality of Individual wire selection system shares a high-frequency signal protective relaying device.
- 6. a kind of Little Current Ground Connection System according to claim 5, it is characterised in that every group of high-frequency signal source produces Symmetrically, the high-frequency signal of three-phase, and the frequency of high-frequency signal differs caused by each high-frequency signal source, it is described every High-frenquency current blocking device in outlet by high frequency electric caused by this outlet high frequency signal source be limited in two high-frenquency current blocking devices it Between outlet in.
- 7. a kind of Little Current Ground Connection System according to claim 1, it is characterised in that the bandpass filter filters out Power current.
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| CN106959402A (en) * | 2017-05-03 | 2017-07-18 | 国网安徽省电力公司培训中心 | A kind of Little Current Ground Connection System and determination methods |
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