CN103668221A - Transformer substation grounding grid corrosion prevention protection construction method - Google Patents

Abstract

The invention relates to a transformer substation grounding grid corrosion prevention protection technology, particularly to a transformer substation grounding grid corrosion prevention protection construction method. When an auxiliary anode is buried, a stuffing capable of improving electrical conductivity is adopted to wrap the auxiliary anode so as to improve the electrical conductivity, and effective and reliable protective current supply is provided for a grounding grid metal used as a cathode; a reference electrode is buried together with the stuffing capable of improving electrical conductivity to enable the reference electrode to measure the electrochemical potential of the grounding grid so as to obtain relatively accurate measurement data and provide a basis for controlling the size of the protective current. Therefore, through the construction method, the corrosion prevention effect can be ensured and completed through one-time construction only, the construction period is short, and the efficiency is high.

Description

Grounding net of transformer substation corrosion protection constructional method

Technical field

The present invention relates to a kind of grounding net of transformer substation corrosion protection technology, particularly a kind of grounding net of transformer substation corrosion protection constructional method.

Background technology

Along with the raising to the security requirement of power supply network, also more and more stricter to the requirement of ground net safe operation, also more and more higher to the requirement of the erosion resistance of grounding material and thermostability.Due to resource and economic dispatch reason, China's ground net material therefor is mainly plain carbon stool or zinc-plated carbon steel.The corrosion of ground net comes from the electrolytic corrosion that the galvanic corrosion in corrosive ground environment of plain carbon stool and zinc-plated carbon steel and the operating discharge current of grid equipment cause.Corrosion makes that ground net material section is long-pending to be reduced, and even fracture, causes ground connection performance bad, jeopardizes equipment and personnel safety, brings huge loss.

In prior art; adopt impressed current formula electrochemical method to avoid ground net corrosion; impressed current electro-chemical protection technology is to control and slow down the extremely effective and very economical of ground net metallic corrosion, the method saving trouble; it is the electrochemical theory based on metallic corrosion; the method of electrogalvanic stream is provided to the ground net metallic substance of underground corrosion by outside; make metal electric potential drop low (cathodic polarization); fundamentally reduce corrosion of metal tendency and erosion rate, reach the effect of the soil corrosion that suppresses ground net metal carbon steel material.Impressed current method cathode protection technology is to rely on outside direct current constant potential/constant-current power supply that the method for cathodic protection current is provided to ground net.It carries required protective current by being embedded in underground supplementary anode to the ground net metal as negative electrode; With a measured ground net electrochemical potential of reference electrode, control the size of protective current.This kind of exportable electric current of method is large and adjustable, and current potential is setup control artificially, long service life, thereby be applicable to adopt in the ground net high at soil resistivity, area is large.

Yet in concrete construction, reaching above-mentioned corrosion protection technique effect also needs with reference to a plurality of factors, the for example structure of supplementary anode, reference electrode, processing and construction, there is no reference standard to concrete construction in prior art, can only rule of thumb implement, cause corrosion protection result not good, repeatedly do over again, time and effort consuming, and construction cost is high, long in time limit, inefficiency.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art part and provide a kind of corrosion protection result good, once constructed, cost is low, the grounding net of transformer substation corrosion protection constructional method that the duration is short, efficiency is high.

The object of the invention is to realize by following approach:

Grounding net of transformer substation corrosion protection constructional method, its main points are, comprise the steps:

Automatic control potentiostat, supplementary anode and reference electrode are provided, and supplementary anode is a kind of buried supplementary anode,

Location and the excavation of position, electrode hole: electrode hole comprises anode hole and reference electrode hole.Through this ground net of cathodic Protection Design calculative determination, adopt buried supplementary anode quantity.Comprehensive and the uniformity requirement according to ground net galvanic protection, determine position, anode electrode hole and phase mutual edge distance and with the distance of ground net.Anode hole cutting depth on average surpasses more than ground net buried depth 300mm.The degree of depth in reference electrode hole is suitable with ground net buried depth, is less than 500mm with ground net distance.

In anode hole, place mat increases the packing layer of electroconductibility, by the horizontal packing layer of supplementary anode, then covers packing layer, with earthen backfill electrode hole, cover tight, and the soil of the upper covering in moistening anode hole of watering; The tie cable of supplementary anode is guided to outside hole;

Reference electrode and the packing layer that increases electroconductibility are together seated in reference electrode hole, with earthen backfill electrode hole, cover tight, and the upper soil covering in moistening anode hole that waters, the tie cable of reference electrode is guided to outside hole equally;

One end of cathode cable is welded on the web plate or counterpoise grounding of ground net, uses sealant sealing solder joint, and with earthen backfill, cover tight,

Automatically control potentiostat scene in place, the tie cable of supplementary anode is connected with the positive terminal of automatically controlling potentiostat; The tie cable of reference electrode is connected with the reference electrode end of automatically controlling potentiostat; The other end of cathode cable is connected with the cathode terminal of automatically controlling potentiostat;

Start and automatically to control potentiostat, measure while not adding galvanic protection, each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, and as initial potential value; Adjustment has added after galvanic protection, and each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, as polarized potential value.

Control and automatically control potentiostat operating parameter index, by power-off, measure, measure the protection potential of each reference electrode place metal, adjust output protection electric current, make protection potential compared with more than metal initial current potential decline 100mV, guarantee electrochemistry corrosion protection effect.In grounding net of transformer substation corrosion protection constructional method of the present invention, supplementary anode is when landfill, the filler that employing can increase electroconductibility wraps up supplementary anode, to increase its conductivity, provides effective, reliable protective current to supply with the ground net metal as negative electrode; Reference electrode is landfill together with can increasing the filler of electroconductibility, can meet its measurement to ground net electrochemical potential, thereby obtains more accurate take off data, for the size of control protective current provides foundation.Therefore by constructional method of the present invention, can guarantee corrosion protection result, only need once to construct and can complete, the duration is short, efficiency is high.

Embodiment

It is example that the present embodiment be take the corrosion protection construction of a certain grounding net of transformer substation.Grounding net of transformer substation corrosion protection constructional method, comprises the steps:

Automatic control potentiostat, supplementary anode and reference electrode are provided, supplementary anode is a kind of buried supplementary anode, and this potentiostat is also a kind of galvanostat, is mainly can non-stop run, it regulates knob to be built in cabinet, can prevent artificial improper malfunction.The present invention selects 1 SF type automatically to control potentiostat/galvanostat; Supplementary anode is selected the buried supplementary anode of SF type, this anode belongs to insoluble anode, has the features such as discharge capacity is large, consumption is low, easy for installation, and supplementary anode adopts filler bag to be coated, can expand the scope of supplementary anode effect like this, reduce soil resistivity.Reference electrode is selected RD type reference electrode.

Location and the excavation of position, electrode hole: electrode hole comprises anode hole and reference electrode hole, and Yi Gai substation is example, through this ground net of cathodic Protection Design calculative determination, adopts 14 of buried supplementary anodes, two anode electrode hole position Average distance 20m.With the range averaging of ground net be 8m.Anode hole 1200mm * 700mm (long * wide).Anode hole cutting depth on average surpasses more than ground net buried depth 300mm, and cutting depth is greater than 1200mm.Reference electrode hole 300mm * 300mm (long * wide).The degree of depth in reference electrode hole is suitable with ground net buried depth, dark 800mm.Reference electrode hole is less than 500mm with ground net distance.

Place mat increase and improve anodic current and conduct electricity inhomogeneity packing layer (filler is comprised of the nut coke that adds certain particle diameter of soil property adjusting agent) in anode hole, by on the horizontal packing layer of supplementary anode, cover again packing layer, with earthen backfill electrode, cheat, cover tight, and the upper soil covering in moistening anode hole that waters; The tie cable of supplementary anode is guided to outside hole;

Reference electrode is placed in to increase electroconductibility and tests inhomogeneity filler (filler is containing components such as neutral sulfatases), bury and be placed in reference electrode hole, with earthen backfill electrode hole, cover tight, and the upper soil covering in moistening anode hole that waters, the tie cable of reference electrode is guided to outside hole equally.。

One end of cathode cable is welded on the web plate or counterpoise grounding of ground net, uses sealant sealing solder joint, and with earthen backfill, cover tight.

Automatically control potentiostat scene in place, the tie cable of supplementary anode is connected with the positive terminal of automatically controlling potentiostat; The tie cable of reference electrode is connected with the reference electrode end of automatically controlling potentiostat; The other end of cathode cable is connected with the cathode terminal of automatically controlling potentiostat;

Start and automatically to control potentiostat, measure while not adding galvanic protection, each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, and as initial potential value; Adjustment has added after galvanic protection, and each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, as polarized potential value.

After having constructed; by automatically controlling the electro-chemical protection device that potentiostat, supplementary anode, reference electrode and cathode cable form, put into operation; wherein the point of reference electrode has at least 5, measures the initial potential value of 3 current potential reference points of the left part, middle part and the right part that are embedded in ground net.The initial potential value of ground net carbon steel metal is listed in table 1:

The initial potential value of each reference point carbon steel of table 1 ground net

Reference 1	Reference 3	Reference 5
			0.785 V	0.815 V	0.780 V

After protector powers up, adjust the output current value of constant potential/galvanostat, make the electrical potential energy of ground net stably than more than initial potential reduction 100mV.Operation result monitoring is as shown in table 2 below.

The potential variation of each reference point carbon steel of table 2 ground net

After ground net electro-chemical protection device puts into operation, the current potential of ground net metal (polarized potential) obviously reduces.From data shown in table 3, the potential drop low amplitude (polarization value) of each reference point is all larger, has all surpassed 100 mV.

The table 3 ground net electro-chemical protection polarization degree of depth

Reference point	Reference 1	Reference 3	Reference 5
				Initial potential V	0.785	0.815	0.780
Polarized potential V	1.069	1.156	1.046
				Polarization value V	0.284	0.341	0.266

After laying by constructional method finishing device of the present invention, table 4 and table 5 are listed the changes in weight that 380 days front and back are buried in carbon steel test piece underground.

Front and back changes in weight is buried in the not protected carbon steel test piece of table 4 underground

Front and back changes in weight is buried in the shielded carbon steel test piece of table 5 underground

The mean value calculation of listed weight loss data in table 4 and table 5, the corrosion protection degree of ground net electro-chemical protection device has reached 91.8 %.Existing form of construction work can reach effect like this far away.

In practice, also adopt NAS novel material as the material of ground net.In test; never shielded carbon steel test piece and NAS test piece bury underground before and after weight loss mean value can see, the average corrosion rate of NAS material (15.79 g/ ㎡) is more much lower than the average corrosion rate of carbon steel material under similarity condition (137.7 g/ ㎡).The average corrosion rate of NAS material is approximately only 1/8th of carbon steel.And the seldom dark corrosion pit in NAS material test piece surface, the performance of its resistance to local corrosion in soil is also far better than carbon steel.Therefore, can predict, the corrosion resistance nature of NAS material ground net in soil and life-span are can be far beyond plain carbon stool ground net.The rust protection protection of enforcement electrochemistry and employing NAS material, power transmission and transforming equipment property safe and reliable to operation improves, or reduces the benefit that abnormal accident, minimizing interruption maintenance etc. bring, and is difficult to especially make quantitative analytical calculation.

Substation's field conduct of a year shows; the ground net electro-chemical protection technology realizing by this constructional method can prevent the corrosion of ground net carbon steel material in soil preferably; not only reduced the average corrosion rate (having reduced more than 90% in the carbon steel test piece of Bei Tou substation) of carbon steel material; but also greatly alleviated the local corrosion degree of carbon steel material, can extend the work-ing life of carbon steel ground net more than one times.Ground net electrochemical techniques anti-corrosion method is all applicable to corrosion protection new, old carbon steel ground net.

The test piece of the NAS material Bei Tou substation that can be used for ground net of research is buried test-results underground and is confirmed, the Corrosion resistance of NAS material can be good, erosion rate only has 1/1/5th～eight of carbon steel, and resistance to local corrosion performance is also considerably beyond carbon steel.NAS material can be for the transformation of overhauling of layout, steel tower and new substation ground network and old earth mat.

It is same as the prior art that the present invention does not state part.

Claims (1)

1. grounding net of transformer substation corrosion protection constructional method, is characterized in that, comprises the steps:

Automatic control potentiostat, supplementary anode and reference electrode are provided, and supplementary anode is a kind of buried supplementary anode,

Location and the excavation of position, electrode hole: electrode hole comprises anode hole and reference electrode hole, anode hole cutting depth on average surpasses more than ground net buried depth 300mm, and the degree of depth in reference electrode hole is suitable with ground net buried depth, is less than 500mm with ground net distance;

In anode hole, place mat increases the packing layer of electroconductibility, by the horizontal packing layer of supplementary anode, then covers packing layer, with earthen backfill electrode hole, cover tight, and the soil of the upper covering in moistening anode hole of watering; The tie cable of supplementary anode is guided to outside hole;

Reference electrode and the packing layer that increases electroconductibility are together seated in reference electrode hole, with earthen backfill electrode hole, cover tight, and the upper soil covering in moistening anode hole that waters, the tie cable of reference electrode is guided to outside hole equally;

One end of cathode cable is welded on the web plate or counterpoise grounding of ground net, uses sealant sealing solder joint, and with earthen backfill, cover tight,

Automatically control potentiostat scene in place, the tie cable of supplementary anode is connected with the positive terminal of automatically controlling potentiostat; The tie cable of reference electrode is connected with the reference electrode end of automatically controlling potentiostat; The other end of cathode cable is connected with the cathode terminal of automatically controlling potentiostat;

Start and automatically to control potentiostat, measure while not adding galvanic protection, each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, and as initial potential value; Adjustment has added after galvanic protection, and each current potential reference point metallographic phase of ground net is for the potential value of reference electrode, as polarized potential value.