Bueno Electric's GPS Sync Clock

1. Overview

Grid dispatching integrated automation system of SCADA function for the dispatcher, set each substation controller provides real-time data and information, and can make them easy to repeat or accident history data and information query. In system design, the need to consider more is network structure, communication protocol conversion, data storage medium and satisfy the requirement of the SCADA function several performance indexes, without taking into account the system so what is the impact of the clock is not synchronized. Because the system so the clock out of sync will cause some of the more special fault, such as data and information loss, SOE event information logic chaos, some workstation crash even system paralysis, so in order to eliminate the influence of the clock out of sync, it is necessary to analyze the clock synchronization in the system and the realization of a variety of ways.

The strong power grid dispatching integrated automation system is a real-time system, it gathers each substation real-time data and information, after processing of the system software on the workstation according to relevant data and information, or stored in the historical database. The dispatching station integrated automation system is divided into factory end system and end system, the main implementation tech-oriented clock synchronization by three parts:
(1) The main end system each workstation with the primary server pair;
(2) Substation end system master control unit with the master station system pair;
(3) Substation end system master control unit and the unit interval intelligent pair.

2. Master station synchronization

The master station, with the purpose of the master server pair is to ensure that data such as add, change, delete operation consistency and completeness of the entire network. Inconsistencies and incomplete data will cause the main case system switch or historical data for storage, can not correctly identify the data consistency and integrity, resulting in the loss of information and data, even lead to paralysis of the system. Due to various workstations and servers crystals chip for a long time after the operation, there will be a clock no problem due to leakage or other reasons, and take the corresponding pair way to realize the main end system network pairs, as shown in figure 1, figure 2 ways:
Main end systems generally do not adopt the way of figure 1 pair way, because the GPS time server only provides a network interface, the other in order to achieve and GPS time setting, all the servers, workstations and front machine need to run the pair process, thereby waste of system resources. Figure 2 pair method, the front machine operation process for fashion pair with the GPS time server, on a regular basis and on a regular basis for servers and network devices, such as radio pair command, which can conveniently realize the pair in the system, thus the main end system usually adopt the way of figure 2 pair way. Data written history library or report timing print is often done in the hour, such as systematic pair at this time will be because of time inconsistency, and cause the loss of data or system failure. Based on this reason, the pair cycle (unit: minutes) should not be divisible number of 60, such as 2, 3, 4, 5 pair cycle also cannot too long, so we suggest using a system pair every 7 minutes. Operation shows that the pair cycle can meet the needs of the system normal operation.

3. Substation terminal synchronization.
GeChang station end system master control unit with the master station system prevailed, and GeChang station end system master control unit, with the purpose of the pair in each interval intelligence unit is to ensure that the data can be gathered by the interval of intelligent information, in the master station system after processing, can correct the time of the repeat data or information, order and logical relations. The dispatcher, set controller according to the display of data and information, a real-time control power system operation state, thus ensuring economic dispatch, security scheduling.

Some of the unattended substation factory end system equipped with GPS time server, and therefore do not need to pair with the master station system. Not installed GPS time server side of the system, through the main terminal pair frontend radio command for fashion, due to the need for data processing, so the pair cycle can be set for a long time, such as 30 minutes. Equipped with GPS time server end system and each interval of the intelligent unit ways pair as shown in figure 3, figure 4 ways:

Bueno Electric's GPS clock is designed for the synchronization of SCADA system, for more product details, please see the product page: http://www.bueno-electric.com/products/gps-clocks-and-time-severs/gps-ntp-time-server.html

As a frequency, time, unified solutions provider, BE assisted in huatai securities recently. Fully illustrates the BE NTP server in terms of quality, performance, and reliability was highly recognition and trust. Our company will continue adhering to the "scientific and technological innovation in the quality first" principle, wholeheartedly for the domestic and foreign customers with high quality, high ratio of performance time and frequency products, services and solutions.

Huatai securities that huatai securities co., LTD., the predecessor to the securities company in jiangsu province, was founded in December 1990, is the first batch of the China securities regulatory commission approved the integrated brokerage, is also one of the earliest national qualification for innovative pilot brokerage.

Bueno Electric as a leader in R & D and production of the GPS NTP time server products, has years of experience in production of commercial, military equipment, the master must have manufacturing network time product core technology, is a leader in the field of the NTP server.

BE's network time server products are widely used in domestic securities industry, the main users include:  securities regulatory commission, the shenzhen stock exchange, the zhengzhou Commodity Exchange, the Shanghai gold exchange, China securities depository and clearing co., LTD., has information technology service co., LTD, China international capital corporation LTD., co., LTD., citic securities building, hongyuan funds, fund of an ancient name for China, jinrui futures, futures, etc., BE's NTP Time Server is the first choice for the securities industry in China.

The Precision Time Protocol (PTP) is a protocol used to synchronize clocks throughout a computer network. On a local area network, it achieves clock accuracy in the sub-microsecond range, making it suitable for measurement and control systems.

PTP was originally defined in the IEEE 1588-2002 standard, officially entitled "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems" and published in 2002. In 2008, IEEE 1588-2008 was released as a revised standard; also known as PTP Version 2, it improves accuracy, precision and robustness but is not backward compatible with the original 2002 version.

"IEEE 1588 is designed to fill a niche not well served by either of the two dominant protocols, NTP and GPS. IEEE 1588 is designed for local systems requiring accuracies beyond those attainable using NTP. It is also designed for applications that cannot bear the cost of a GPS receiver at each node, or for which GPS signals are inaccessible.

The Precision Time Protocol (PTP), defined in IEEE standard 1588, enables precise synchronization of device clocks in packet based networks. Devices are automatically synchronized to the most accurate clock in the network. The protocol supports system wide synchronization accuracy, usually in the sub microsecond range, with minimal network and local clock computing resources. The protocol is used in applications such as test and measurement, power-line management, industrial automation and telecoms.

PTP accuracy is based on an assumption that the delay in Ethernet is approximately constant and symmetric. The protocol is a master-slave type and it includes a Best Master Clock selection algorithm that organizes the clocks in the network to form a tree-like structure: master clocks use the BMC algorithm to determine whether they should remain master clocks, or follow some better master. Non-master clocks use the BMC algorithm to determine which master clock to follow, or whether to become master clocks themselves. A few different types of clock exist:

A master clock typically has an external clock source connected to it, or it has a very accurate internal time reference, for example an atomic clock. A master clock is a source of time information for the PTP network.
A slave clock uses the PTP protocol to follow the time of its selected master clock.

A boundary clock is a clock that is located between two or more network segments. A boundary clock acts as a slave clock in one of the network segments, and as a master in the other segments. Boundary clocks forward the clock information from one network segment to another.

Transparent clocks forward clock information in the same way as boundary clocks, but they are not visible to the IP layer or to the PTP protocol. A transparent clock can , for example, be integrated into an Ethernet switch, so that the switch modifies PTP frames on-the-fly, minimizing the effect of its own packet queuing delays to the synchronization accuracy.

Version 2 of the IEEE1588 standard was released in 2008.

Power Line Communication (Power Line Communication, English abbreviation PLC) technology is the use of Power Line transmission data and media a way of Communication signals. The technology is the high frequency load carrying information on current and then wire transmission accept information adapter to separate from high frequency current and transmitted to the computer or phone in order to realize information transfer.
Power Line communication full name is the Power Line Carrier (Power Line Carrier - PLC) communication, is refers to the use of high voltage Power Line (in the field of Power Carrier) usually refers to more than 35 kv voltage grade, medium voltage Power Line (10 kv voltage level) or low voltage distribution lines) as the medium of information transmission (380/220 v for voice or data transmission is a kind of special communication mode.
Power cat "power line communication Modem", namely the broadband Internet access via the power line Modem commonly known as. Use a home or office existing powerline and formed into a network socket, to connect to PC, ADSL modem, set-top boxes, audio equipment, monitoring equipment, and other intelligent electrical equipment, to transmit data, voice and video. It has the characteristics of plug and play, can pass the ordinary families power line transmission network IP digital signal.

The development Phases

In the past
Power line communication technology appeared in the early 1920 s. Application instance of power line transmission signal, as is power line phone, its application range is within the same power supply circuit of transformer, the electrical signal from a powerline filter down. In 1991, the electronics industry association identified three family bus, power line is one of them. In October 1997, Northern Telecom company announced a digital wire technology development, the technology will make the electric power company can transport on the power line at a rate of 1 MBPS data and voice services. Later, Siemens PLC technology will power bus family is extended to the village of telecommunication access network port, and can transmit data at a rate of about 1 MBPS.
Technological progress has accelerated. By cisco, Intel, HP, panasonic and sharp 13 companies and established "family plug Alliance" (HomePlugPowerline Alliance), is committed to create a common household electrical wiring network communications technology standard.

Europe is not weakness. Information technology show in Hanover, Germany, the German power industry giant RWE power company introduced a new technology named power network, this new transmission technology will be able to all kinds of Internet data transmission via power line signals, thus greatly promote the popularity of the Internet. Users only need to take a few minutes, the special modem with the ordinary wire into the socket, you can surf the web, the speed can also be at 2 million MBPS broadband standard. The Bundestag parliament's upper house recently passed a bill, approved for use to make the Internet information through the power line and power socket on the wall transmission technology.

Japan will make a connection in the 2001 years of technical standards. Kyushu electric power company and the Tokyo electric power company and mitsubishi electric, Fujitsu, panasonic and other cooperation, the development of transmit and receive image through the power line technology, practical products and is scheduled for 2001 years.

In China, in the 1940 s has Japanese production of carrier machine running in the northeast of China, as a long distance scheduling methods of communication. Since 1999, China began to research institute for the high speed PLC is studied, and in August 2001, established the first experiment network in shenyang. Again since December 2001, guodian communications center began to organize the domestic and foreign manufacturers of PLC application experiment in the residential area in Beijing these companies include South Korea Xeline ASCOM (14 Mb/s system), Switzerland company (4.5 Mb/s) system, the Leap (14 Mb/s), the Spanish company DS2. Fujian electric power test research institute (10 Mb/s systems), as well as electricity institute (14 Mb/s system), etc. China's fujian province electric power test research institute developed "digital transmission technology" of the core products - power modem and multiple related products, its transmission rate up to 10 m. The guodian communications center USES the power line communication (PLC) network equipment at home and abroad, a living community in Beijing lnternet access tests have been carried out successfully, and get the ideal effect. With the deepening of the research, PLC also develops to a higher rate. To increase the rate to 100 Mb/s, for example, or even 200 Mb/s. At the appointed time, high speed PLC will make a greater contribution for broadband communications.

The status
Electric power communication network is in order to guarantee the safe and stable operation of power system and arises at the historic moment. It with the power system security and stability control system, dispatching automation system are collectively known as power system safe and stable operation of the three pillars. It is the marketization of power grid dispatching automation, network operations and the basis of the modern management; Is to ensure that an important means of power grid security, stability, economic operation; Is one of the important infrastructure power system. Due to the electric power communication network reliability, protection and control of communication information transmission and the quickness and accuracy of strict requirements, and the power sector has special resource advantage for the development of communication, therefore, most countries in the world of power companies are established in the form of self-built primarily for power system communication network. [1]

Traditional power line carrier communication (PLC), which make use of high voltage transmission line as the high frequency signal transmission channel, limited to transmit voice, remote control signal, such as narrow application range, transmission rate is low, cannot satisfy the demands of the development of broadband networks. PLC is to develop in the direction of large capacity, high speed, at the same time to communication with low voltage distribution network carrier, realize the home users using the powerline phone, Internet and other business. Abroad, such as the United States, Japan, Israel and other countries are carrying out a research into the low voltage distribution network communication and test. By the 3 com, Intel, Cisco, Japan panasonic, 13 companies jointly set up using power line as the transmission medium of Home network to promote group, "Homeplug PowerlineAlliance", has put forward Home (Home) plug-in socket plan, aimed at promoting power line as the transmission medium of digital family (DigitalHome).

There are two problems to be further study:
(1) Hardware platform: mainly includes the selection of proper communication, the communication network structure optimization selection, etc. Way of spread spectrum and OFDM technology and multi-dimensional grid coding modes have their own advantages, which is suitable for DiYaWang remains to be seen, or it can use the idea of software radio for the three ways to provide a unified platform. Power grid structure is very complex, network topology, how to optimize the network structure is also worth studying problem.

The basic principle
When sending, use of modulation technology to user data modulation, the high frequency load carrying information on current, and then transmitted on power line; At the receiving end, take out modulation signal through the filter, after demodulation, can get the original signal, and transmitted to the computer or phone, in order to realize information transfer. PLC end and modem equipment bureau, bureau of end with internal PLC modem communication and connection with the external network. In communication, from the user data into the modem modulation, through user distribution circuit transmission to office equipment, office end to signal demodulation, and then transferred to the outside of the Internet. Concrete two-way transmission power line carrier module design idea: by the modulator, oscillator, power amplifier, T/R in parts, such as switches, coupling circuit and the modem transmission module, the oscillator is a carrier signal for modulator. When firing data, momentum after the issue of the signal from the TXD modulation by the modulator, then modulated signal to the amplifier amplification, after T/R to switch and the modulated signal coupling circuit load to the power line. When receiving data, emission module to send the modulated signal by coupling circuit and T/R to switch into the modem, the modem to extract the original signal after demodulation, and the original signal from the RXD end to the next level of digital devices.
Interface type
Power line communication equipment commonly used interface is as follows:
RJ - 45
RJ - 45 interface is the most commonly used interface, Ethernet RJ - 45 is a commonly used name, refers to the standardization of IEC 603-7 (60), using the defined by the international standard connectors of eight (8) needle position modular jack or plug.
USB
USB (Universal Serial Bus) Universal Serial Bus (USB) is made by Intel, Microsoft and Compaq, IBM, NEC, launched several big manufacturers such as a new type of peripheral interface standards. USB1.1 transmission speed of 12 MBPS, USB2.0 is up to 480 MBPS; The maximum length of 5 meters cable. USB cable with 4 lines, of which 2 line, 2 power cords, can provide 5 v power supply. USB cable is shielded and unshielded two, shielded cable transmission speed can be up to 12 Mbps, more expensive and not shielded cable speed of 1.5 Mbps, but cheap; USB can connect up to 127 by way of series equipment; Support plug and play and hot plug.

Modulation method
Power line communication usually adopts the debugging method for OFDM, namely orthogonal frequency division multiplexing. OFDM is under severe electromagnetic interference of communication environment, technical measures to guarantee the stability of data transmission complete HomePLUG 1.0 specification covers 4-21 MHZ communication frequencies, in this frequency division within the 84 OFDM communications channel. The principle of OFDM is a few communication channel according to the 90 degree phase frequency division, the result is that when a particular channel wave passing zero when the waveform of the adjacent channel is right is the maximum amplitude, thus ensure the channel between the waveform will not overlap, crosstalk by outside interference.

Nanjing airport is an important air transport hub, is a modern large airport. The airport has electronic bell 94, while construction of the departure system, flight information display system, broadcasting system, dispatching system, information security systems, building automation systems, security monitoring system, parking lot management system, call center system and other information systems, these systems are connected to each other through the interface of collaborative work, consistency time is very important. Through the construction of the clock synchronization system, the system will be unified clock calibration, for each system to lay a solid foundation for cooperation.
1, The application of the clock in the airport and the necessity of clock synchronization
The communication network of communication equipment or computer equipment time information (the date when) based on UTC (UTC) time limit deviation in a sufficiently small range (such as 100ms), this process is called synchronization time synchronization.
Airport departure system according to the time signal at the appointed time opening and closing check-in; FIDS flight information display at the specified time; broadcast system broadcast in time to remind the booking information to guide passengers; building automation system to control the lighting, air conditioning according to the time of opening and closing; command and dispatch system by time accurate airport information command department cooperative work; each picture in security monitoring system must record the time information; parking lot management system relies on the exact time charge parking fees; call center according to the time information to guide passengers; passengers and staff also need accurate time information.
An accurate clock system is an important basis for the normal functioning of the various production systems.
2, The realization of clock synchronization system
2.1 Function introduction
The star structure, set up a NTP server, receiving the standard time signals from GPS, set up a high precision clock, clock time for receiving signals from the NTP, and the clock signal through the transmission subsystem to each sub clock into / departing passengers and airport staff to provide a unified standard time. At the same time clock output (with millisecond signal) standard time signal to the NTP network time server, by the time the NTP web server through a computer network system to provide uniform time signal to the coordination of the airport terminal and the production of the business operation Department, the electromechanical system timing device and system clock synchronization.
2.2 clock system components
Composed of the clock system mainly consists of GPS receiver, clock, sub center clock, world clock, NTP server, transmission channel and management control computer.

2.2 NTP (network time) server
Network time server receives the GPS standard time information, and sends this information to the standard time clock. Network time servers can provide standard time information for networked computers over ethernet.
The GPS antenna is properly installed and standard time signal into the control center communication room, connected to the network time server back, turn on the power switch, the network time server to start work, after a period of time, the front panel display local standard time.
2.3 GPS clock
As the basic clock master clock of the whole clock system, it can receive standard time signal from the network time server, calibrate the time precision of its own, and the precise time allocated to each sub clock signal. The clock is the central part of the whole system, the stability of the work largely determines the reliability of the whole system, therefore, should fully consider the comprehensive factors of the realization of the system function and system reliability, the system design, configuration of the machine unit to pay, and between the main and auxiliary machine can realize automatic or manual switch. Standard time clock sending and receiving network time server through a standard RS422 interface signal. Network time server during normal operation, the signal will be used as the time base of the master clock; network time server fails, the master clock will be used for high stability crystal oscillator itself as the time reference. The master clock through a standard RS422 interface to the standard time signal clock sent after calibration, and the operating state information receiver Zi Zhong echo, and can be controlled by the clock work status information back to the monitoring terminal, displayed on the monitor computer. The master clock through the standard RS232 is connected to the monitoring computer interface, to achieve the monitoring of the main equipment of the clock system, and time control computer.

Specifications:

The BE-PTP-011 model PTP Time Server is a standard PTP clock server, by the extented BMC (Best Master Clock) algorithm, PTP TimeServer can quickly select the high precision clock source to sync with. PTP TimeServer can be synchronized to absolute time such as GPS, Galileo, BD-Star systems. The reference clock can also be synchronized to external time through an external GPS interface or IRIG-B interface. It has multiple functions of master clock, slave clock and boundary clock through the operating mode of the software configuration system.The time output accuracy can reach less than 50ns.
Providing 11 time code outputs, the device adopts the flexible method of plug-in card, and may configure the output interface flexibly. The output signals contain time synchronization signals of PPS (Pulse per Second), PPM (Pulse per Minute),RS232,RS485, Ethernet, IRIG-B (DC), IRIG-B (AC), IRIG-B (Manchester), 10KHz, serial port time message and network time service, with each way output signal mutual isolation electrically.
As a top-ranking clock server, PTP Time Server could choose the installation of internal OCXO or rubidium atomic clock, making the device have a better timekeeping ability; meanwhile the clock control algorithm in the system outputs the time information stably in a certain period of time to keep certain time service accuracy.

Feature and Benefits:

• Standard PTP TimeServer, with GPS(Global Positioning System), by the extented BMC (Best Master Clock) algorithm,PTP TimeServer can quickly select the high precision clock source to sync with.
• Flexible deployment of the interface board
• Optional BD-Star or GPS
• Equipped with clock control algorithm, and with the performance of perfect timekeeping
• Optional atomic clock or OCXO
• Supporting 11-channel time code outputs.
• Supporting high precise 1PPS/1PPM, IRIG-B code, TCP/IP code outputs
• Supporting RS-232/485 serial port time service
• Time delay compensation function
• Supporting NTP/SNTP network time service
• Supporting PTP network setting time
• Supporting visualization operation management
• Dual redundant power supplies
• Star Search Performance,can display the locked satellites number
• GPS locking time: Warm Start:29s Cold Start:35s Hot Start:<1s
• BD locking time: warm Start:20s Cold Start:80s
• Five years warranty & life long maintenance
• Small quantity OEM is acceptable
• Work Temperature:-20˚C to 75˚C
• Storage Temperature:-40 to 85℃
• Ambient Relative Humidity: 10 to 95%(Non-condensing)

Research and Markets has announced the addition of the"Global Industrial Ethernet Market 2016-2020" report to their offering.

The report forecasts the global industrial Ethernet market to grow at a CAGR of 15.03% during the period 2016-2020.

Increased use of Ethernet among machine and robot OEMs will be a major key trend for the market. Robot and machine OEMs are increasingly employing industrial networks to connect their controllers, distributed I/O, human machine interfaces (HMIs), instruments, and sensors to each other within a machine or a robot. Ethernet is becoming the network of choice for robots, machine OEMs, and end-users because of its ubiquity and better price/performance ratio over other communication networks.

According to the report, one of the key drivers for market growth will be growing implementation of IIoT. IoT is a network of physical devices embedded with sensors, software, and hardware that enable to gather and exchange the data without human intervention. We predict 50.2 billion devices to be connected to the Internet by 2020. Approximately 40% of these devices will be smart devices such as televisions, tablets, and smartphones. The remaining will be made up of devices that are not traditionally Internet-enabled.

Further, the report states that one of the challenges for the market will be emergence of wireless connectivity and WSNs in industrial automation and control.

10 IEC-61850 subsations in Thailand made by Nanjing Nari control system company have been all completed and put into operation. The project successfully put into operation for further products and services Nari has accumulated a good reputation in Thailand market.

Thailand's new 10 station renovation project for turnkey EPC project, Nanjing by Nari control system company to undertake the project reconnaissance, design, supply, transportation and field installation, debugging and commissioning and acceptance of work.

10 substations by Nari independent research and development of NSS201 communications and data processing device, NS3500 measurement and control device and NS3000S background monitoring system. The system currently has successful application in Bangkok, Thailand, 55 substations, stable operation of the system, a simple interface, by the owners Bangkok City Electric Power Company (MEA) recognition.

The 10 substations of the project are distributed around the capital of Bangkok, Thailand, to provide a solid guarantee for the stability of Bangkok power grid.