This kind of device is applied to the overhead power distribution network automatic system from 6KV to 35KV,is used to improve the safe and reliable operating performance through centralized monitoring the current, temperature and fault condition on the power distribution circuit.

Short-circuit principle:

when phase-to-phase short-circuit happens, it is equivalent to directly connected between two power, there will be a very large current flowing through the return circuit of substation and fault point, meantime, the relay protection equipment in the substation will start on protection according to the well-setting rules, which will make the lines switch off. So there are 4 conditions to judge the short-circuit fault as following:

1)there is electricity in line

2)a sudden change large current is above a certain value (this value can be set by actual condition after leaving factory)

3) The large current duration time is not more than 3 seconds 0.02s≤△T≤3s, △T is duration of sudden change current.

4)The line will be in the state of power off in 3 seconds.

5)When it meets all the four conditions above, the indicators can judge the short-circuit happened in this line and send the fault information to central station.

Earth fault detection principle:

When single phase earthed happens, many kinds of complex transient phenomenon according to different earthed conditions such as metal earthed, high resistance earthed. The transient state phenomenon includes the distributed capacitor discharge current of line-to-ground, the earthed line voltage to ground is decreased. For all these phenomenon, the judging criteria of earth fault of our products is as following:

1)there is sudden increased transient state capacitor current in the line: the current is above a certain value

2)the earthed line voltage is decreased 3KV above.

3)judgment of detecting earthed current power direction.

When the three conditions above can be meet, the detecting terminals can judge the fault point where is after the alarming indicators which will send the fault information to the central station.

System Composition Structure and detailed instruction:

This system of device is composed of communicable fault passage indicator, data transmission unit, main station software and hardware.

There is type test report for it, test items as following:

Beijing TIANYIHONGDA Science & Technology Development Co., LTD is located in Lize Business Circle area, a prosperous business area in the center of Beijing City, China. is a high and advanced technology enterprise which is professionally engaged in research, production, sales and service of advanced smart monitoring technology products. We have great professional research team and techniques service team with rich working experience in the field of smart monitoring technology, cooperating with many famous Universities and Science Research Institutions on Smart Grid Automation, Smart Sensors and Wireless Communication and developing widespread market.

Our company has a great achievement in the development of Smart Grid, we by ourselves researched out the whole set of power distribution automation products such as DTU, FTU, RTU and so on. The central products and technology obtain national patents and certificate issued by relevant authoritative institution. The Fault Passage Indicators and Fault Location DTU systems has been stably running nearly 820,000 sets in the big city and middle city in domestic and overseas Market. accumulation of rich techniques and practical running experience on sites, these devices not only applied in the areas of national state grid, railway, petroleum, chemistry, coal, but also widespread used in the overseas countries such as India, Vietnam, Sri Lanka, Indonesian, Iran, Brazil, South Korea, South American and so on.

Meanwhile, the company is also successfully developing products to new monitoring fields, researched out Meteorological Monitoring Equipment, Environmental Monitoring Equipment and Video Monitoring Equipment and so on. All the products got the authoritative type test report and fully carry out and implement ISO9001 Quality Management System, these equipments have been successfully sold to domestic and overseas markets and approved by our clients.

Solar Power system with remote monitoring function is also successfully entering into market and get approval by the users. we have succefully finished many projects including commercial,residential applications for on-grid and off-grid applications such as 40KW substation, 60KW substation, residential ,countryside etc.

“ Sincerity is fundamental, clients is the first” & “strict quality control, earnest service supply” are our company’s management ideal, we sincerely invite all the cooperation partners working together to supply good qualities of products and service to domestic and overseas clients, devote ourselves to electrical smart grid development and monitoring technology development.