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Substation system over-voltage protection technology文献


Substation system over-voltage protection technology

Second substation equipment over-voltage protection on electronic information system for the protection of core equipment for the construction of a protected both pressure and other potential system, and through all levels of over-voltage surge protectors of the current step by step into the land of China, Substation secondary safety equipment and reliable operation. 1 second over-voltage substation protection In recent years, systems, the substation communications, background

communications

protection

systems,

management module frequent over-voltage damage, the main reason for this is weak and its related systems products over-voltage protection level is weak, or no guard against over-voltage Technical measures, the consequences for the safe operation of power grids bring about a greater negative impact. With integrated automation systems and automation systems such as communication systems in the substation weak secondary by the wider use of such electronic systems (equipment) components of the integrated more and more, the growing volume of

information storage, speed and accuracy of the Increased and operates only a few volts, current information only microamp level, thus extremely sensitive to outside interference, especially the lightning and electromagnetic pulse, such as over-voltage tolerance is low. When thunder and lightning, such as over-voltage and accompanied by the electromagnetic fields reach a certain threshold, ranging from system failure caused, resulted in heavy equipment or permanent damage to its components. Despite the thunder and lightning viewpoint of electronic systems (equipment) is unlikely, but lightning strike near the land, buildings, communication and air supply line directly Leiyun discharge form, or because of

electrostatic induction and the impact of electromagnetic induction formation of over-voltage, There might be connected to the power lines, signal lines or grounding system, through various interfaces to transfer, coupling, radiation and other forms of invasive electronic system (equipment) and lead to serious disturbances or incidents. Therefore, strengthening and improving the electronic system (equipment) protection, to minimize the impact of interference by lightning and other damage caused direct losses and indirect losses, has become the urgent need to solve the problem.

2 over-voltage protection design IEC (International Electrotechnical Commission) TC/81 mine technical committee will be divided into internal and external mine mine in two parts, the external mine is lightning rod (or with lightning, lightning network), Yin Xiaxian and grounding system, Objects to be protected from direct lightning strikes, mine is to prevent internal lightning and other internal over-voltage damage caused by invasive equipment. A comprehensive mine and over-voltage protection systems must be integrated use of discharge (segregation), both pressure (and other potential), shielding (isolation), grounded, limit pressure (clamp) protection, and other technology, in

accordance with the external mine And the principle of internal mine, in accordance with the targets of protective features, flexible application to take concrete measures, constitute a complete protection system. Over-voltage substation in the form are: Lightning over-voltage, the resonant frequency over-voltage and over-voltage, over-voltage operation, these over-voltage transmission or electromagnetic induction to the way the lines and equipment on a dangerous over-voltage, in particular, Lightning over-voltage, lightning substation, in the low-voltage power supply system and weak system to produce

a strong over-voltage sensor, while the substation to potential rise (for example: the substation grounding resistance to 1 Q, lightning current 10 kA, while the potential for 10 kV), due to the increased potential of the counter lines and equipment damaged lines and equipment and the events have occurred, therefore, despite the substation outside the mine system (lightning rod. Yin Xiaxian And grounding devices) in line with national standards and the requirements of Buban, and the integrated automation and communications automation systems, such as weak secondary have been taken, such as shielding, grounding, isolation, filtering, and other measures, but it can not completely avoid over-voltage powerful lightning And voltage of the system counter the disruption caused damage and, therefore, the second weak system substation and a mine-voltage must also take the appropriate protective measures, in accordance with the IEC within the mine area EMP, the device's power cord, signal Lines, data lines, and the installation of lightning protection and internal over-voltage devices to prevent lightning sensors, channeling people along the lightning current, voltage counterattack, such as transient voltage surge too transient over-voltage caused by a fault and damaged electronic equipment. Over-voltage surge protection in

accordance with its connection mode is divided into two series and parallel, the use of over-voltage surge protection tandem with, there may exist because of signal transmission does not match the causes of transmission of the signal interference, in particular data Communication Interface in the series were over-voltage surge protection in place, will have the normal data communications. Therefore, the data communications access I: I in the series were over-voltage surge protection in place, the transmission of data must be carried out conscientiously check if the data are not normal transmission, it may be due to the reasons do not match the transmission signal

Interference, should be replaced to match the over-voltage surge protection for. If the use of over-voltage surge protection for use of parallel, the situation is basically non-existent, but the connection mode of over-voltage surge protection for higher technical requirements. 3 secondary system over-voltage substation protection 3.1 points over-voltage electricity system protection Substation installed in the communications dispatch automation systems are used AC power or a DC power supply equipment for the rectification of its links are generally larger capacity filter capacitance, the transient over-voltage

shock absorption of a certain extent, the station Low-voltage transformer side go to feed between the screen using a shielded cable and equipment have a good grounding, the use of modern technology to analyze mine, we must increase the circuit's segregation measures, because its grounding, protection and other electrical grounding all Grounding devices using the same equipment, and equipment are in a LPZOB, the relative strength of strong electromagnetic pulse, the station changed to prevent low-pressure side although there are lines intrusive wave arrester, but the residual pressure high, in the substation of lightning, through the line Coupling and the potential rise caused by over-voltage counterattack still exist, and

high-pressure side of the residual pressure as high as several thousand volts, it is necessary to these scheduling automation equipment for the power supply over-voltage circuit protection. Lightning Protection in accordance with the principle of regional division, substation equipment in the secondary power supply system over-voltage sensors lightning protection may be two (B, C level) for the protection of segregation. B-mine use is generally greater flow capacity of the mine installations, the Lightning could be more casual Liuxie people, to achieve the objective of current limit, over-voltage at the same time

will reduce to a certain extent, c-mine use With lower residual pressure of the mine installations, you can loop in the remaining scattered lightning Liuxie people, to limit the purpose of over-voltage, over-voltage equipment can be reduced to the level of tolerance. The main power supply system is inhibited lightning protection and operation of the power back to the road and over-voltage surge. According to the substation status of the substation of the second mine-sensing system and the operation and use of two over-voltage protection. As build more substations in the region more open, relatively strong electromagnetic strength, power lines and communication cables are very vulnerable to lightning attacks sensors, sensors along the over-voltage power lines and communication lines into one device, which will damage equipment, Therefore, the exchange of first-class bus to install the power protection (B level) is to ensure the safety of the entire control room, and 80 percent of the over-voltage China, scattered to the earth, play a primary role in the protection, but are still in the exchange of feeder Some of the B-level power supply voltage and mine the residual pressure increases on-line and must therefore be important in the exchange of feeder lines (DC charging screen, UPS, etc.) c-level power protection, which would curb

over-voltage electrical equipment to back-end To the level of tolerance.Protective location: It is 1 EC1312 (LEMP protection "in the region of lightning protection principles. Arrester installation should be in different locations at the junction of protected areas, this network, the first-class protection should be located in the bus exchange. In Two on the bus with the installation of a B-class models of a three-phase power supply voltage surge protector. Install Location: AC bus (cabinet). 3.1.2 second-class protection measures to deal with For the more important feeder lines on the exchange of equipment, here for the DC charge screen, the installation of c-level three-phase power arrester. As DC charging screen is two-way exchange of electricity supply, so the screen in the DC charge with the installation of two models of c-level three-phase power supply over-voltage surge protector.

Installation location should choose the DC charge screen open exchange of air power Commissioner Office. 3.2 integrated automation system over-voltage protection Protective position: Computer-based integrated automation system's ability to bear a very low voltage, several hundred volts of over-voltage is enough to damage the equipment, so must

the high side arrester the residual pressure (thousands of volts) to further curb to meet equipment Insulation level of need, and because of the potential rise to power and the induction loop is also over-voltage line up on KV, to be used in the exchange of integrated automation system to the exchange on the c-level single-phase installation of a surge Voltage protection. Location should choose to install automated-ping in the Composite Air switch the AC power. 3.2 integrated automation system over-voltage protection Protection here: because of the internal computer systems, hubs, monitoring equipment, electric energy billing systems and so on through the UPS power supply protection, in order to protect the safety of these micro-electronics equipment, the UPS power supply device in front of the installation of a c-Surge Voltage protection. Optional models: The (UPS for single-phase power input) C-class single-phase power surge or over-voltage protection (UPS for the three-phase power input) of c-level three-phase power supply over-voltage surge protector. Installation should choose the location of UPS into the front line. 3.4 communication interface over-voltage protection Communication Interface over-voltage protection compared

with the grid supply system, this over-voltage circuit on the degree of sensitivity is much higher, and these are

over-voltage equipment in the circumstances it is very fragile. Equipment insulation tolerance level is very low. With the equipment connected to a signal line, data lines, measurement and control lines, and these are basically in line LPZOB region, but also through the LVZOA region, on the lines of sensors over-voltage relatively strong, according to the IEC test, when the electromagnetic field Strength increased to 0.07 GS, will have a micro-computer equipment malfunction, loss of data. And the safety of these circuits is directly related to a system of safety equipment, so important to be on the interface circuit over-voltage protection. 3.4.1 remote computer interface devices over-voltage

protection Protective position: As substation computer remote

installations scattered distribution structure. From remote modules, intelligent telemetry module, intelligent remote control module, intelligent remote-module. The modules are installed in different automated-ping, through the RS232 interface between the modules or field bus communication. These interfaces are in the indoor circuit, equipment interface

circuits shorter the distance, so there will be no more sensors to the over-voltage, but the automation equipment and other secondary equipment (measurement unit, computer, etc.) have electrical connections, when Other secondary equipment sensors to a strong over-voltage sensors, will be counter to these automation equipment, communications interface, so that damage to equipment interface circuits, it is necessary in these devices RS232 interfaces on the installation of a surge Voltage protection. Installation location should choose the remote computer interface devices, communications lines. 3.4.2 electric energy billing system signals over-voltage protection A protective position: a multi-functional electronic power substation table, energy acquisition, the electronic power meter to bear a very low voltage levels. As Meter and remote computer stations in the communications equipment used RS232 interfaces, the communication line is longer, and in LVZOB region, near the substation or by direct lightning strike at the substation, proximity to the high voltage sensors, In order to prevent damage to equipment. E-Meter in and around the RS232 port RS232 installation of the over-voltage surge protector. Location should choose to install electronic power meter in and

around the port, RS232. The location of protection: electronic power meter through the acquisition of information on the collector's MODEM (modem) from telephone lines to send data to a remote, since the introduction of telephone lines from the outside, the lines on the sensor to sensor lightning current relatively strong, easy to Modem interface equipment damage, it is necessary in the telephone line modem interface, the installation of an interface over-voltage surge protector. Location should choose to install telephone Chuxian inside and outside phone lines-the-line people. 3.4.3 distance communication interface over-voltage

protection Protective position: Since the basic use of unmanned substation. On the first circuit protection, measurement, control, regulation of signal through the optical and data communications network or carrier to the distance (in tune, and stressed that the centralized control stations, etc.) to transmit data. If the carrier, the carrier and the computer automation of the signal devices connected relatively long lines, substations in the vicinity of a direct lightning strike or substations.Should be a strong over-voltage sensors, to be

near the computer automation devices to signal I: I-the installation of signal arrester, while in the area and extend to LPZOB LPZOA area of communication lines (DDN, X.25) very easy Lightning sensors on the over-voltage, must also be the installation of over-voltage surge protector. Installation location should choose the remote device communication line interface Department. Secondary system over-voltage substation protection

issues in recent years by a new task, the above is only related to the scene of the unit into the actual situation on the Protection of the preliminary measures, it will be in continuing to draw on practical experience of running a summary analysis and continuous improvement, Hope that the new substation in the future or the old substation automation of integrated, strengthen the secondary over-voltage protection system of planning and design, equipment and ensure the safe and stable operation of power grids. Substation relay protection, fault recorder, local and remote monitoring not only of different functions, and the realization of the principles and techniques are also different. Thus, the long-standing expertise in different technologies and the corresponding management departments. With the

microprocessor-based protection, computer control and remote computer devices, such as widely used, it was noted that despite the different functions of these devices, the hardware configuration is the same, the collection and to control many of the same object. Thus, it appears from the overall situation to consider the idea of substation automation. However, in substation automation technologies, the implementation

process of the relay, measure, control, remote features, as well as the relationship between them, are still some problems worthy of our study. The following currently used for many domestic substation automation design practical, from the secondary system analysis and comparison of several aspects. 1 System structure The whole system level by the station management, industrial bus network layer and spacing layer is composed of three parts, the system of all monitoring, protective equipment are modular units of the structural design, according to the voltage substation level, the size can be flexible and user requirements. Because of the centralized system is no longer used, it is no longer here, the following describes only the structure of distributed systems.

1.1 Function-oriented distributed systems A function of each unit completed, the system functions can be divided into: AC and DC measurement unit, remote acquisition unit, remote control and operation unit, pulse energy collection units, such as the protection unit. The advantages of such systems is the functional unit with the communication bus between the complete separation of the electrical, any fault on the system unit has no effect on the rest of the system. The disadvantage is that multi-screen group, the relative complexity of the second wiring, poor scalability,

decentralized units can not be installed. 1.2 Interval-oriented distributed systems Power transmission line to substation is divided into a number of intervals, such as into the line spacing, transformer spacing, round layout. Relatively independent of the spacing of equipment, only through the Internet communication network stations with station-level computers to communicate. Interval of each layer by telemetry, remote, remote control, the protection of the distribution of multi-CPU configuration, and the introduction of computers in the design of local area network technology, the distribution function, as far as possible the principle of decentralization, which, though

greatly improved the reliability of, any interval failure will not affect the other partitions, but the reliability of each interval is relatively low, if any interval a fault will affect the whole interval. 1.3 Object-Oriented Distributed Systems That is, a unit of an object into each line, each round, each transformer, capacitors can be targeted. This is a true full-distributed substation automation system, which broke the original limits of the functions of the second device, in accordance with the requirements of substation automation reorganization. This object-oriented distributed systems in line with the International Electrotechnical Commission's technical specifications, is the future direction of

development. It has the following features: greatly improved system reliability, partial failure does not affect the system; relatively independent modules, each affected small; data sharing good; system efficiency; multi-function integrated control approach, making the operation of equipment management very simple, low maintenance; anti-interference ability; good scalability; stations needed the Second cable greatly reduced, saving investment. 2 Dual-bus network and a single network structure

Stand-level management and monitoring layer to protect the data and commands between the transmission network can be double or single network structure. Hub for the 110kV substation, a dual network structure to facilitate a large flow of data to ensure rapid delivery when all kinds of signals, and to improve its reliability. Dual-network approach, usually an independent group to monitor and protect the network, in the transmission line or electrical equipment fault protection actions, the network can be used to protect the rapid transmission of recorded wave data. Substation 110kV and below, as a result of a smaller scale, data throughput, 110kV and below a single network substation can well meet the requirements of data transmission. 3 integration of monitoring and protection Since the technology level of the special status of protection and management system problems, long-term

protection and monitoring has been separated. However, with the electricity sector, the gradual changes in management and computer and digital communication technology's rapid

development, low-voltage level (eg, 35kV, 10kV) substation, in order to reduce the investment cost, ease of operation and management and improve the level of automation, control and

protection

of

suitable

integration

unit,

which

is

characterized by: monitoring and protection together to protect the independence of TA and TA to monitor access, this is to ensure the accuracy of measurements, but also improves the reliability. Hardware standardization, the same as the unit of hardware, software is different from the same template can be interchangeable, the measurement accuracy is not affected after the swap will design, help a users complete maintain and master. main

Object-oriented

sampling.

The

protection and back-up protection of a strict separation of the main transformer protection and high and low pressure side of the back-up protection is a small unit, and backup protection for each side of the design, the same unit within the strict separation of the protection of exports. Flexible

configuration unit may focus on group screen, the installation can also be dispersed. There are configuration functions, a variety of ways to protect the flexibility to access and removal. This structure has not been widely used at present because of: the professional management of the current power grids are separated from the protection and remote, using this structure to change the management system, operation and maintenance

personnel at the same time demands a higher level. Reliable operation of such systems is one of the keys to the hardware unit to monitor the protection must adapt to poor working conditions, need to have a strong anti-jamming, anti-vibration capabilities, able to adapt to high temperature and high humidity of the working environment; second is to have a efficient and reliable fast data communications networks. Due to the design of the reasons, the integration of monitoring the protection of unit failure, there is no monitoring and the protection of a clear interface, it is difficult to find and distinguish the scope of failure. 4 RS485 or CAN field bus network Distributed system of communication there are serial communication bus mode and network mode, which is the most typical RS485, the latter applies to more typical substation environment Controller Area Network CAN.


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