Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Patent
1989-11-24
1991-12-03
Eisenzopf, Reinhard J.
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
324535, 455 12, H04B 1700, G01R 3108
Patent
active
050705377
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a system for detecting any defective point on a power transmission line by making use of a highly-accurate time signal transmitted from a satellite and by utilizing a digital data processing system. In contrast to conventional analog type detection system which can provide a detection accuracy on the order of several kilo-meters at the highest, the detection system of the present invention enables detection at an accuracy on the order of several meters.
BACKGROUND ART
Detection systems which are presently available are classified into a surge-receiving-type detection system and a pulse-radar-type detection system.
The surge-receiving-type system can be sorted into a power-line transmission system and a microwave radio transmission system.
A description will be given of the construction and operation of conventional surge-receiving-type detection system.
FIG. 1 illustrates the construction of a detection system of a power-line transmission line (generally referred to as a "B-type system").
A power line is cut due to a thunder-bolt at a point marked by 1 in this Figure. As a result of the cutting, a surge pulse is transmitted as indicated by 1.fwdarw.2 and 1.fwdarw.3. The surge pulse received at a subordinate station is sent to a master station through a route 4.fwdarw.5. It is therefore necessary that the transmission delay time t.sub.3 incurred during the surge pulse transmission 4.fwdarw.5 be exactly detected. In the master station, the time t.sub.1 at which the surge pulse is received at the electric station A and the time which is obtained by subtracting the time t.sub.3 from the time t.sub.2 +t.sub.2 of the surge pulse received at the electric station B, i.e., the time t.sub.2. and computes the distance between the station A (or the station B) and the point of cutting of the power line, in accordance with the result of the comparison. The computed distance is then delivered to, for example, an automatic printing device.
A description will be given of a detection system of the microwave radio transmission type.
FIG. 2 shows the construction of the detection system of the microwave radio transmission type (generally referred to as "micro-B-type").
This system is based on the same detection method as the power line transmission type system, but is different from the latter in that a microwave circuit is used as the means for transmitting the surge signal from a subordinate station to the master station.
In this system, 12 microwave circuits or so are exclusively used for this purpose.
On the other hand, the detection system of pulse radar type is as follows.
Namely, a detection pulse is transmitted through the power transmission line and the pulse reflected by the defective point is received so that the distance to the defective point is computed by measuring the time until the reflected pulse is received.
A description will be given of the drawback of the surge-receiving-type detection system.
The power-line transmission-type system, which is one of the surge-receiving-type system, has a drawback that it essentially requires a coupling device because this type of detection system utilizes the power transmission line a the detection circuit.
Another problem is that the exchange of the signal is impossible when the defect exists in the phase (one of three phases) used for the signal transmission. Thus, the probability of receipt of the signal is 2/3.
In addition, error tends to be caused in the detection because of noises and surges which affect the detection signal.
Furthermore, it is necessary that the transmission delay time be exactly grasped. (Slight difference in the transmission delay time occurs to cause an error)
In order that the detection is conducted within a tolerance of 1 km, the change in the transmission delay time has to be within about 3 .mu.sec as will be understood from the following equation.
In addition, error tends to be caused in the detection time due to collapse of the waveform, because of the use of the analog signals. Namely,
REFERENCES:
patent: 4792963 (1988-12-01), Campanella et al.
patent: 4932070 (1990-06-01), Waters et al.
Ohira Sakari
Ozawa Masaaki
Terashima Akira
Yamaki Masatoshi
Eisenzopf Reinhard J.
Kyokuto Boeki Kaisha Ltd.
Pham Chi H.
Tohoku Electric Power Co. Inc.
LandOfFree
System for detecting defective point on power transmission line does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for detecting defective point on power transmission line , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for detecting defective point on power transmission line will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1701386