CN101017972A - A method for preventing the device from electric shock danger - Google Patents
A method for preventing the device from electric shock danger Download PDFInfo
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- CN101017972A CN101017972A CN 200710026911 CN200710026911A CN101017972A CN 101017972 A CN101017972 A CN 101017972A CN 200710026911 CN200710026911 CN 200710026911 CN 200710026911 A CN200710026911 A CN 200710026911A CN 101017972 A CN101017972 A CN 101017972A
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Abstract
The disclosed method avoiding danger of electric shock comprises: deciding whether the step voltage and touch voltage over pre-set threshold; if yes, reducing two voltage values under the safe level. This invention reduces electric shork danger greatly without effect on injecting fault current or lightning current in ground.
Description
Technical field
The present invention relates to the communications field, relate in particular to a kind of method that prevents device from electric shock danger.
Background technology
Electric shock is commonly called as electric shock, is caused by human body by electric current.Shock current will produce the pathologic physiological effect by human body or animal body, for example contraction of muscle, expiratory dyspnea, blood pressure raise, form heart excitation wave, atrial fibrillation and do not have the fibrillar of short duration cardiac arrest of ventricle, ventricular fibrillation, until death.The degree that human body is subjected to electric shock is relevant with size by body current, frequency, duration etc.Electric current is big more, and the duration is of a specified duration more, and the extent of injury that human body is subjected to is high more.
In engineering practice, equipment (such as communications equipment room and communication base station) electric power system breaks down or under the situation of thunderbolt, all can produce very big electric current, thereby produce dangerous voltage on element of installation, for guaranteeing the safety of the person and equipment, need equipment ground.By ground connection is that fault current and thunder-strike current are provided to the ground path.But the earth is not a perfact conductor, has certain resistivity, therefore, when electric current when earth electrode injects the earth, can spread towards periphery with the form of current field, can in soil, produce pressure drop simultaneously and form certain surface potential distribution.Therefore, when the people walks about near earth electrode, people's bipod will be on the different potentials point of big ground surface, can form the potential difference between bipod, and this potential difference is called step voltage.Accordingly, when going to contact earth electrode with hand near the ground the people stands on earth electrode, also can form potential difference between people's hand and the pin, this potential difference is called touch voltage.Facts have proved, when step voltage and touch voltage surpass a certain safety value, will cause shock hazard when electric current flows through human body.
Summary of the invention
The embodiment of the invention provides a kind of method that prevents device from electric shock danger.Can guarantee that equipment fault electric current or lightning current inject the earth simultaneously smoothly, reduce device from electric shock danger greatly.
A kind of method that prevents device from electric shock danger that the embodiment of the invention provides comprises: judge that whether step voltage and touch voltage surpass default safety value, if the judgment is Yes, reduce described step voltage and described touch voltage below described safety value.
Wherein, described described step voltage and described touch voltage are reduced to the earth resistance that is specially below the described safety value by reducing described equipment ground net reduces described step voltage and described touch voltage below described safety value.
Wherein, the described earth resistance that reduces described equipment ground net is specially the earth resistance that reduces described ground network by the surface area that increases described ground network.
In addition, described described step voltage and described touch voltage are reduced to the resistivity that is specially the surface soil by increasing described equipment ground net region below the described safety value reduces described step voltage and described touch voltage below described safety value.
Wherein, the resistivity of the surface soil of the described equipment ground net of described increase region is specially by lay the resistivity that gravel or asphalt concrete increase the surface soil of described ground network region on the face of land.
In addition, described described step voltage and described touch voltage are reduced to being specially the gradient that distributes by the surface potential that reduces described equipment ground net region below the described safety value reduces described step voltage and described touch voltage below described safety value.
Wherein, the described gradient that reduces the surface potential distribution is specially by bury equal pressure zone in soil and reduces the gradient that surface potential distributes.
Further, described method is further comprising the steps of: detection of ground faults, and when detecting earth fault, excise described fault.
Implement the embodiment of the invention, have following beneficial effect:
The embodiment of the invention is by judging whether step voltage and touch voltage surpass default safety value, and in judged result when being, described step voltage and described touch voltage are reduced below described safety value, realized guaranteeing that equipment fault electric current or lightning current inject the earth simultaneously smoothly, reduce the purpose of device from electric shock danger greatly.
Description of drawings
Fig. 1 is the schematic flow sheet of first embodiment of the present invention's method of preventing device from electric shock danger;
Fig. 2 is the schematic flow sheet of second embodiment of the present invention's method of preventing device from electric shock danger;
Fig. 3 is the schematic flow sheet of the 3rd embodiment of the present invention's method of preventing device from electric shock danger.
Embodiment
In engineering practice, equipment (such as communications equipment room and communication base station) electric power system breaks down or under the situation of thunderbolt, all can produce very big electric current, thereby produce dangerous voltage on element of installation, for guaranteeing the safety of the person and equipment, need equipment ground.By ground connection is that fault current and thunder-strike current are provided to the ground path.But the earth is not a perfact conductor, has certain resistivity, therefore, when electric current when earth electrode injects the earth, can spread towards periphery with the form of current field, can in soil, produce pressure drop simultaneously and form certain surface potential distribution.Therefore, when the people walks about near earth electrode, people's bipod will be on the different potentials point of big ground surface, can form the potential difference between bipod, and this potential difference is called step voltage.Accordingly, when going to contact earth electrode with hand near the ground the people stands on earth electrode, also can form potential difference between people's hand and the pin, this potential difference is called touch voltage.Facts have proved, when step voltage and touch voltage surpass a certain safety value, will cause shock hazard when electric current flows through human body.Therefore, the embodiment of the invention is by judging whether step voltage and touch voltage surpass default safety value, and in judged result when being, described step voltage and described touch voltage are reduced below described safety value, realized guaranteeing that equipment fault electric current or lightning current inject the earth simultaneously smoothly, reduce the purpose of device from electric shock danger greatly.
For the purpose, technical scheme and the advantage that make the embodiment of the invention is clearer, the embodiment of the invention is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is the schematic flow sheet of first embodiment of the present invention's method of preventing device from electric shock danger.As shown in the figure, the method for present embodiment specifically comprises:
Step S100 judges whether step voltage and touch voltage surpass default safety value, execution in step S101 if the judgment is Yes; Otherwise, stop.As previously mentioned, in engineering practice, equipment (such as communications equipment room and communication base station) electric power system break down or the thunderbolt situation under, the capital produces very big electric current, thereby on element of installation, produce dangerous voltage,, need equipment ground for guaranteeing the safety of the person and equipment.But ground connection can produce step voltage and touch voltage again, when step voltage and touch voltage surpass a certain safety value, will cause the phenomenon that shocks by electricity.Therefore, in practice, be necessary step voltage and touch voltage are controlled in certain safety value, to prevent shock hazard.
Step S101 reduces described step voltage and touch voltage below described safety value by the earth resistance that reduces described equipment ground net.Facts have proved that earth resistance is directly proportional with step voltage and touch voltage, therefore reducing earth resistance can reduce step voltage and touch voltage.
In isotropic the earth, earth resistance R can be expressed as:
In the following formula, proportionality constant ρ and ε depend on the electrical properties of the earth, the earth resistance R of earth electrode and its capacitor C are inversely proportional to, and the size of electric capacity depends primarily on the size of the surface area of ground network, therefore the size of ground network surface area and the size of earth resistance are inversely proportional to, in the practice, can reduce the size of earth resistance, and then step voltage and touch voltage are reduced below default safety value by the surface area that increases ground network.
Step S102, detection of ground faults, and when detecting earth fault, excise described earth fault.Human body is subjected to the electric shock degree not only relevant with the size of current by human body, and also relevant with the duration of electric shock, the duration is short more, and the injury that human body is subjected to is just more little.In the practice, can pass through detection of ground faults, and when detecting earth fault, excise described earth fault and shorten the electric shock time.
Fig. 2 is the schematic flow sheet of second embodiment of the present invention's method of preventing device from electric shock danger.As shown in the figure, the method for present embodiment specifically comprises:
Step S200 judges whether step voltage and touch voltage surpass default safety value, if the judgment is Yes, and execution in step S201; Otherwise, stop.This step is identical with the step S100 of embodiment one, at this repeated description no longer.
Step S201, the resistivity of the surface soil by increasing described equipment ground net region reduces described step voltage and touch voltage below described safety value.When between human body people's or when standing bipod and soil, there is contact resistance to exist at ground running.For calculating step voltage and the touch voltage that the people produces at ground running or when standing, can be people's pin that the disk of 0.08m is approximate with a radius, utilize the earth resistance of disk in the uniform soil to calculate formula, can try to achieve the contact resistance R between every pin and soil during at ground running as the people
0≈ 3 ρ.
Draw thus, as people during at ground running, the virtual voltage between the human body bipod is that step voltage is:
When the people stands on ground and catches when touching terrain, people's hand and the virtual voltage between pin are that touch voltage is:
According to above formula, the electricalresistivity of increasing surface soil can increase the contact resistance R between people's pin and soil
0Thereby, reduce step voltage and touch voltage, therefore, the resistivity of surface soil that can be by increasing the earth electrode region in the practice increases the contact resistance between people's pin and soil, and then step voltage and touch voltage are reduced below default safety value.
Step S202, detection of ground faults, and when detecting earth fault, excise described earth fault.This step is identical with step S102 among the embodiment, at this repeated description no longer.
Fig. 3 is the schematic flow sheet of the 3rd embodiment of the present invention's method of preventing device from electric shock danger.As shown in the figure, the method for present embodiment specifically comprises:
Step S300 judges whether step voltage and touch voltage surpass default safety value, if the judgment is Yes, and execution in step S301; Otherwise, stop.This step is identical with step S100 among the embodiment one, at this repeated description no longer.
Step S301, the gradient that distributes by the surface potential that reduces equipment ground net region reduces described step voltage and touch voltage below described safety value.In the practice, can reduce the gradient that surface potential distributes by lay equal pressure zone on the face of land of ground network region.Such as, can near import and export, aisle and the equipment of base station, lay equal pressure zone, to change the Potential distribution on the face of land, reduce the gradient of Potential distribution, and then described step voltage and touch voltage are reduced below default safety value.
Step S302, detection of ground faults, and when detecting earth fault, excise described earth fault.This step is identical with step S102 among the embodiment, at this repeated description no longer.
Above disclosed only is preferred embodiment of the present invention, can not limit the present invention's interest field certainly with this, and therefore the equivalent variations of doing according to claim of the present invention still belongs to the scope that the present invention is contained.
Claims (8)
1, a kind of method that prevents device from electric shock danger is characterized in that, comprising: judge that whether step voltage and touch voltage surpass default safety value, if the judgment is Yes, reduce described step voltage and described touch voltage below described safety value.
2, the method for claim 1, it is characterized in that described described step voltage and described touch voltage are reduced to the earth resistance that is specially below the described safety value by reducing described equipment ground net reduces described step voltage and described touch voltage below described safety value.
3, method as claimed in claim 2 is characterized in that, the described earth resistance that reduces described equipment ground net is specially the earth resistance that reduces described ground network by the surface area that increases described ground network.
4, the method for claim 1, it is characterized in that described described step voltage and described touch voltage are reduced to the resistivity that is specially the surface soil by increasing described equipment ground net region below the described safety value reduces described step voltage and described touch voltage below described safety value.
5, method as claimed in claim 4, it is characterized in that the resistivity of the surface soil of the described equipment ground net of described increase region is specially by lay the resistivity that gravel or asphalt concrete increase the surface soil of described ground network region on the face of land.
6, the method for claim 1, it is characterized in that described described step voltage and described touch voltage are reduced to being specially the gradient that distributes by the surface potential that reduces described equipment ground net region below the described safety value reduces described step voltage and described touch voltage below described safety value.
7, method as claimed in claim 6 is characterized in that, the described gradient that reduces the surface potential distribution is specially by bury equal pressure zone in soil and reduces the gradient that surface potential distributes.
8, as each described method among the claim 1-6, it is characterized in that, further comprising the steps of:
Detection of ground faults, and when detecting earth fault, excise described fault.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN 200710026911 CN101017972A (en) | 2007-02-13 | 2007-02-13 | A method for preventing the device from electric shock danger |
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| CN 200710026911 CN101017972A (en) | 2007-02-13 | 2007-02-13 | A method for preventing the device from electric shock danger |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104021297A (en) * | 2014-06-13 | 2014-09-03 | 国家电网公司 | Method for lowering step voltage |
| CN111786349A (en) * | 2020-06-09 | 2020-10-16 | 深圳供电局有限公司 | Step voltage suppression method for power transmission line tower |
| CN112524921A (en) * | 2020-11-19 | 2021-03-19 | 林晓霞 | Device for uniformly printing and air-drying plate during plate making process |
| WO2023237290A1 (en) * | 2022-06-10 | 2023-12-14 | crop.zone GmbH | Monitoring apparatus for monitoring a treatment apparatus for crops |
-
2007
- 2007-02-13 CN CN 200710026911 patent/CN101017972A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104021297A (en) * | 2014-06-13 | 2014-09-03 | 国家电网公司 | Method for lowering step voltage |
| CN111786349A (en) * | 2020-06-09 | 2020-10-16 | 深圳供电局有限公司 | Step voltage suppression method for power transmission line tower |
| CN111786349B (en) * | 2020-06-09 | 2021-12-07 | 深圳供电局有限公司 | Step voltage suppression method for power transmission line tower |
| CN112524921A (en) * | 2020-11-19 | 2021-03-19 | 林晓霞 | Device for uniformly printing and air-drying plate during plate making process |
| WO2023237290A1 (en) * | 2022-06-10 | 2023-12-14 | crop.zone GmbH | Monitoring apparatus for monitoring a treatment apparatus for crops |
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