English master to 2000 words translation

Fiber optic communications

Even though optical fibers are far smaller than wire duals, and silica (the most widely used material in fibers) , is far more abundant than copper, the cost of compiling rods from which fiber optic comes out to be several times greater than the cost of production wires1 In addition, studies have shown that this may be true for some time in this case.

However, the fiber optic system, which can be used to carry out and make more telephone conversations at the same time than the filament double, can carry them, so far from amplifying the regeneration, which at this time, there are many telephone calls to carry out between points such as switching off the ICE, the fiber optic system is economically attractive2. Therefore, the inter-departmental backbone will be the first to benefit from this new technology.

Competition is tougher, though, with existing high-capacity systems using coaxial cable transmission lines, waveguide, microwave radios and satellites. Larger fiber bandwidth, reduced losses, and more reliable light sources make fiber more competitive in this sector.

The heart of an optical communication system is the one in which electrical signals are transmitted: to a telephone, computer or cable TV. A light-emitting diode or laser converts these signals into pulses of light, which travel along a glass fiber. At the receiving end, a light detector converts the signals back into electrical signals.

This system offers significant advantages over traditional ones that rely heavily on electronic signals and copper wires. Included, is the processing of large amounts of information; a high-performance laser can generate up to 0.5 billion light pulses second. Therefore, it is possible to transmit the entire 30 volumes of the Encyclopaedia Britannica in a tenth of a second, because optical communications are not subject to electromagnetic interference, and thus can cause noise copper cables, they present clear signals, despite the proximity of power lines or electric motors.

Copper wires, although they are insulated, can leak electronic signals and cause crosstalk in nearby power lines. Not so with optical communication equipment. Fiberglass cables, moreover, weigh only about one percent as much as copper wires carry the same number of signals. In fact, a half-inch thick one can carry as many signals as a copper wire as big as a man's arm. At the time, also because fiberglass carries light rather than electricity, there was no danger of sparks in dangerous environments, such as chemical plants or nuclear reactors.

Power Line Carrier Communications

Power Line Carrier (PLC) was first introduced in 1920. Since then. PLC technology has evolved into a mature and reliable communication technology for power transmission systems, and today is used primarily for relay protection, SCADA and voice data transmission systems.

Programmable controllers use carrier frequencies to transmit information over existing transmission lines. The carrier frequencies applied to transmission lines are typically 20 kHz and 300 khz.Information is encoded on the carrier by employing Amplitude Modulation (AM) in a one-sided frequency band (single sideband), and Frequency Shift Keying (FSK signaling). At the transmitter side, the modulated carrier is injected into a transmission line through a coupling capacitor and a tuner. The modulating signal propagates down the transmission line to the receiving end. At the receiving end, the coupling capacitor and tuner split the PLC signal from the high-frequency supply voltage and a demodulation extracts the information encoded in the signal. Trap lines at both ends of the route, preventing carriers from traveling down unwanted paths.

PLCs do well on transmission systems because they are electrically simple and have few interruptions; typically, PLCs are assigned a frequency of use from 5 kHz to 20 kHz. Generally frequencies less than 20 kHz are called distribution line carriers [diamond-like] and use is allowed on a non-licensed, non-interfering basis. For this reason, when we talk about a PLC system that is used in a utility's distribution system, we refer to it as diamond-like. Unfortunately, distribution circuits are electrically complex because of the presence of numerous junctions, transformers and shunt capacitors. These severely attenuate the carrier frequency, making it difficult to reliably advertise a signal through the internal distribution system. In an attempt to rectify this problem, carriers are distributing systems that utilize much lower frequencies than with transmission systems. These are much closer to the power, frequency, and therefore less likely to be attenuated by the large number of parallel capacitors found on distribution systems. Despite the significant improvement, their use of lower frequencies has not eliminated the problems associated with attenuation and drug problems. In addition, signal "holes" are a serious problem. The hole occurs at a point where the DLC signal reflects a canceled event class diamond signal. Signal reflections are due to discontinuities such as transformers and line ends. When a DLC system is designed, studies are made to select a carrier frequency where the holes minimize the difficulties. Future modifications of the distribution system can change the location of the holes or create new ones, which may interfere with the DLC system. Special techniques must be employed by the DLC system to correct this problem, just as special techniques must be employed by radio and telephone to correct this problem.

There is considerable argument for the ability of the class Diamond to get past faults and to area outages. PLCs on the transmission system can provide additional paths for the carrier through single-phase faults as the remaining phases. In this case of a midpoint fault, the carrier can recouple from the neighboring phases into a faulted phase farther away from the fault. For distribution systems, there are also many sections that are single phase and do not allow this. Also, there are portions of fault conditions, such as broken conductors, that will prevent drugs from passing through to the distribution system. Bypassing the route tuning equipment allows class diamond signals to be sent close to reclosers and switches, making it possible to become communicating in areas where power is out.

Distribution line carriers have the ability to transmit data at sufficient rates for most distribution automation programs. With today's technology, data rates for typical diamond-like systems run at ranges from 5 to 20 kHz, which is 300 baud or less. Distribution line carriers have two bi-directional capabilities that are economical to implement for multiple functions, such as remote meter reading (rmr), as well as retrieving load data from points on the distribution feeder.

Diamond-like has the advantage of having been used successfully, which is regulated under the utility, reaching all points, the distribution system of the utility, and the requirement of no FCC license. Despite these advantages, the drug problem has limited data transmission rates. Class Diamond can play an important role in distribution automation, but it is unlikely that alone it will be able to fulfill all its necessary communications for distribution automation.

Other wired communications

Telephone and TV cable are the 2 types of wired communications;

Telephone is a well-established and highly mature communication technology, and it is a widely used tool for monitoring and relay protection. From a technical point of view, telephony is suitable for distribution automation. The telephone system, provides the capability of high data rates and has been built. In addition, it is easy to implement in a two-way configuration. Unfortunately, the cost of leased telephone lines is high, and utility bills cannot control the quality of the telephone lines and their communications. These drawbacks make telephone communication more attractive to distribution automation than it be.1 In addition, some places are not accessible, which is more expensive to the point of local line service. The use of dial-up connections to telephone lines reduces the cost compared to leased lines, but these are much slower due to "dial-up time" and will be very slow in performing functions such as fault isolation and restoration of power, Telephone lines have been used successfully in distribution communication systems, but utilities continue to look for alternative systems that are regulated by the utility and do not have a leasing fee.

The area that is available to operate through the cable television system, mainly coaxial cable as a signal transmission path. Signal amplifiers are placed on the system in necessary. Cable television systems have a vast bandwidth, a significant portion of which is unused. Distribution automation can utilize a very small portion of this available bandwidth. Most cable systems are designed for one-way rather than two-way communication. Many utility customers do not subscribe to cable television. Cable TV suffers from the same drawbacks as telephones, these are considered to be under external control, and there is the possibility of being charged a rental fee for their use.

Wireless communication

Radio has proven itself to be a viable communication technology for certain distribution automation functions. Radio is a wide-ranging communications technology that requires little or no hard signaling and can be implemented in a two-way configuration. All radio systems have the ability to communicate to areas with power outages.

Radio communication technology is available in the following forms:

morning broadcast

FM radio

VHF

UHF

microwave

satellite

morning broadcast-

Radio systems, which are no longer commercially available for distribution of load control, utilize morning broadcasting stations to transmit information to a large number of load control units, located in distribution systems. that are situated in the distribution system1 . This system is feasible by encoding load control information on the very broadcast carrier. The information is encoded using phase modulation and is not detected by ordinary radio receivers, so listeners will not detect any degradation in the high quality of the radio waves, which are sufficiently long compared to the VHF waves to indicate that they curve around the norizon superior to VHF signals, and do not degrade tracking multipath distortion to the same extent as VHF signals. This makes AM broadcast carriers suitable for communicating with large numbers of receivers in remote locations and other areas of geographic diversity.

fmsca -

Another system utilizing radio FM SCA. The Secretary for Constitutional Affairs claimed a subsidiary communications authorization. Basically, the FMSCA signal is multiplexed into a group of carriers in an FM radio mode, frequency modulated. Ordinary radios are not aware of this system and are specially equipped with receivers that can decode the protocol messages. FM CAB is a way out and will certainly make the communication system suitable for the same purpose as the AM broadcast system. An unfavorable FM protocol is the FM broadcast signal, which, because of its shorter wavelength, is more susceptible to multipath distortion, as is the case and is limited to the line of sight. In crowded or rugged terrain, FM protocols are likely to check out coverage more than AM systems.

VHF Radio -

Radio waves with frequencies of 30 and 300 MHz are categorized as VHF (very high frequency). Utilities considering VHF radio systems for distribution automation will find only 3 available frequencies. Utilities enjoy a 300 watt, 3000 Hz bandwidth channel around 154 MHz with two 50 watt 3000 Hz channels that are also available for distribution. Many utilities use these 3 channels for load control communications and there may be limitations, access and extensive coordination issues from competing utility rates. Licenses are issued by the PCC and will be required for utilities to operate the system. VHF signals have limited range and are also susceptible to multipath distortion and tracking. Due to the caveats that must be taken into account when operating this system; costs can be prohibitive to reach 100% coverage. Despite these drawbacks, VHF radios have been used in a number of unidirectional operational load control systems and have been used in the ability to communicate to outage areas, essentially under utility control and with low initial cost of ownership.

UHF Radio Waves -

Radio systems operating at frequencies ranging from 300 to 1,000 MHz are classified as UHF (Ultra High Frequency). Recently, the U.S. Federal Communications Commission approved an application for a frequency range from 940 to 952 MHz for utilities. This opens up new possibilities to utilities that have not considered radio in the past, due to overcrowding and interference on existing VHF frequencies. Radio systems operating in the UHF range are more susceptible to atmospheric absorption, multipath distortion and shadow effects than radio systems operating at lower frequencies. Nevertheless, radio systems in this range prove themselves to be quite reliable and less subject to interference, making for a more competitive service. Data rates up to the 9600 band have been demonstrated on these new UHF channels. In addition, UHF antennas are smaller than VHF antennas due to the shorter wavelength. At this high frequency, wave propagation is essentially limited to the line of sight. In mountainous areas, UHF radio waves may not be a viable alternative.

Microwave

Microwave communications use frequencies higher than 1 gigahertz. Microwaves are currently used utility rates for applications in SCADA and relay protection. Utilizing microwave communication systems, distribution automation is not possible except as the final link from the substation RTU to the distributiondispatchcenter . This is due to the high cost and complexity of setting up microwave systems. Microwave is not suitable for applications where multipoint communication is required. It is a point-to-point communication technology that maintains its economic viability for two main reasons. It can replace a hardware signaling channel and it has high bandwidth. For power distribution automation, the data rate requirements and path lengths are so small that the more typical microwave applications, i.e., the effective cost per channel becomes very high, making microwave unattractive for distribution automation unless it is used in a point-to-point high data rate configuration.

Satellite

Today, most satellite communications are made by means of a satellite in geosynchronous orbit. Satellite transponders have been receiving uplink signals relaying it at different frequencies. Due to their high altitude, satellites provide a wide uniform signal coverage. Communication that can be done via satellite, it is to be leased or own transponder on the satellite and have the necessary uplink and downlink equipment. Microwave frequencies are commonly used for both uplink and downlink. Some utilities successfully utilize satellites for monitoring, but due to the 1/4 second delay on the early path with geosynchronous satellites, they cannot be used to monitor functions that require very fast response times (e.g., relay protection). The use of satellites for distribution automation is also under consideration.

Spread Spectrum Communications

Spread Spectrum Communications transmits many short messages via low-power transmitters that do not require a license. The frequency band transferred is 902 MHz to 928 MHz.

This solution also requires a relatively large amount of radio communication equipment, repeaters and RTU devices to transmit data over a wide area. In addition, combining data and voice is not possible, so the infrastructure can not use the benefits.