The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of t...The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products.展开更多
In this paper, a method to calculate the slope of the ratio restraint characteristic of a transformer differential relay protection is proposed. The method allows using some concise but effective means to get the slop...In this paper, a method to calculate the slope of the ratio restraint characteristic of a transformer differential relay protection is proposed. The method allows using some concise but effective means to get the slope. Modulating the argument of current output from ONLLY testing equipment can make the relay protection device operate, thus, the data used for calculation would be obtained naturally after several trails. In order to make sure how effective that method could be, some experiment data is given as well.展开更多
The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can ...The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also展开更多
OOS （out-of-step） condition prevention becomes an imperative task to avoid possible power system blackout and collapses. To be confident in correct OOS relaying, the OOS protection device behavior under the vast maj...OOS （out-of-step） condition prevention becomes an imperative task to avoid possible power system blackout and collapses. To be confident in correct OOS relaying, the OOS protection device behavior under the vast majority of power system abnormal regimes should be tested. Comprehensive testing procedure becomes especially important for complex power systems when power system parameters and consequently device settings are not clearly defined or may vary in time. For such complex systems the real OOS protection device testing may become a problem because of specific waveforms of signals persisting during OOS condition. The goal of the methodology, presented in the paper, is to achieve the possibility of out-of-step protection device testing under close-to-real power system operation conditions. The power system stability modelling software is used as a source of test signals. The accurate model of power system in conjunction with dynamical modelling features allows to verify the reliability of OOS protection scheme under consideration as also allows the device settings correction, if necessary. The methodology allows to test the real device with signals waveforms which are hardly obtainable using traditional testing technique.展开更多
In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of sci...In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of scientific instruments on board.The system design of Queqiao-2,including mission orbit and transfer orbit design,configuration and layout design,housekeeping and information flow design,power supply and distribution design,GNC and propulsion system design,communication links design,etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity,availability,schedule,cost,and so on.With a view to reducing development risk,both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant spacecraft.Queqiao-2 features flexible system architecture to support multiple frequencies,modulations,data rates and software reconfigurations to meet new user requirements.Subsequent to a successful launch on March 20,2024,by means of 5 orbit maneuvers,Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on schedule.Following on-orbit tests and calibrations,Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions,as well as the capacity to perform scientific observations.Under the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far side.In the meanwhile,Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′e-8.The design life time of Queqiao-2 is more than 8 years.Benefit from flexibility and extensibility of relay communication system design,it is convenient to provide relay communication services for future lunar exploration missions of both China and other countries.In addition,innovative scientific observations would be performed during the period that no relay communication task is arranged.The system design of Queqiao-2 reflects the development philosophy of technical innovations and inheritance integration.Based on highly flexible and extensible system architecture,multiple and concurrent relay communication mission requirements can be met.It can provide strong supports for future lunar exploration missions.Successful launching,orbit entering and on-orbit tests of Queqiao-2 verified the correct design principle and versatility.By means of Queqiao-2,more innovative scientific outcomes are anticipated and lunar exploration activities can be facilitated.展开更多
The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating cond...The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating conditions. This paper proposes a test method to prevent and circumvent the failure of the dynamic test abnormality caused by the static power test before the plant power is applied and the whole group is started. Reduce the dynamic test workload and test difficulty, to ensure that the dynamic test safety risk control and control in the state.展开更多
With the rapid development of network technology and communication technology, all walks of life are moving towards the direction of intelligence, which has greatly promoted the social and economic progress in our cou...With the rapid development of network technology and communication technology, all walks of life are moving towards the direction of intelligence, which has greatly promoted the social and economic progress in our country. The power industry is no exception. The emergence of smart substations has greatly improved some problems existing in the operation and maintenance of Chinas power industry and played a key role in promoting the long-term development of smart grids. More importantly, the relay protection technology has also been greatly changed under the support of the smart grid. Based on this background, strengthening the research work on the operation and maintenance of relay protection has an extremely far-reaching guiding role, which is helpful to promote the sustainable development of Chinas power grid construction.展开更多
In the process of EFT / B immunity test, due to the influence of high frequency interference, the difference of test layout and test parameters may lead to the inconsistency of test results, thus affecting the reliabi...In the process of EFT / B immunity test, due to the influence of high frequency interference, the difference of test layout and test parameters may lead to the inconsistency of test results, thus affecting the reliability of each port test of relay protection device. This paper describes the possibility of uncertainty in each link of the test process, and analyzes the influence of reducing the uncertainty of EFT / B immunity test on the test results.展开更多
基金Project (No. E2005000039) supported by the Natural Science Foun-dation of Hebei Province, China
文摘The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products.
文摘In this paper, a method to calculate the slope of the ratio restraint characteristic of a transformer differential relay protection is proposed. The method allows using some concise but effective means to get the slope. Modulating the argument of current output from ONLLY testing equipment can make the relay protection device operate, thus, the data used for calculation would be obtained naturally after several trails. In order to make sure how effective that method could be, some experiment data is given as well.
文摘The paper intfoduces a PC-DSP based real-time digital simulator which is portable in size and aimed at the closed-loop testing of various types of protective relays for their design and application. The simulator can be widely used in not only concerning utilities but also manufacturers and research / certification institutes because of its many functions. The hardware architecture and software implementation of the simulator are described. The main features and functions of the simulator are also
文摘OOS （out-of-step） condition prevention becomes an imperative task to avoid possible power system blackout and collapses. To be confident in correct OOS relaying, the OOS protection device behavior under the vast majority of power system abnormal regimes should be tested. Comprehensive testing procedure becomes especially important for complex power systems when power system parameters and consequently device settings are not clearly defined or may vary in time. For such complex systems the real OOS protection device testing may become a problem because of specific waveforms of signals persisting during OOS condition. The goal of the methodology, presented in the paper, is to achieve the possibility of out-of-step protection device testing under close-to-real power system operation conditions. The power system stability modelling software is used as a source of test signals. The accurate model of power system in conjunction with dynamical modelling features allows to verify the reliability of OOS protection scheme under consideration as also allows the device settings correction, if necessary. The methodology allows to test the real device with signals waveforms which are hardly obtainable using traditional testing technique.
文摘In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of scientific instruments on board.The system design of Queqiao-2,including mission orbit and transfer orbit design,configuration and layout design,housekeeping and information flow design,power supply and distribution design,GNC and propulsion system design,communication links design,etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity,availability,schedule,cost,and so on.With a view to reducing development risk,both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant spacecraft.Queqiao-2 features flexible system architecture to support multiple frequencies,modulations,data rates and software reconfigurations to meet new user requirements.Subsequent to a successful launch on March 20,2024,by means of 5 orbit maneuvers,Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on schedule.Following on-orbit tests and calibrations,Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions,as well as the capacity to perform scientific observations.Under the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far side.In the meanwhile,Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′e-8.The design life time of Queqiao-2 is more than 8 years.Benefit from flexibility and extensibility of relay communication system design,it is convenient to provide relay communication services for future lunar exploration missions of both China and other countries.In addition,innovative scientific observations would be performed during the period that no relay communication task is arranged.The system design of Queqiao-2 reflects the development philosophy of technical innovations and inheritance integration.Based on highly flexible and extensible system architecture,multiple and concurrent relay communication mission requirements can be met.It can provide strong supports for future lunar exploration missions.Successful launching,orbit entering and on-orbit tests of Queqiao-2 verified the correct design principle and versatility.By means of Queqiao-2,more innovative scientific outcomes are anticipated and lunar exploration activities can be facilitated.
文摘The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating conditions. This paper proposes a test method to prevent and circumvent the failure of the dynamic test abnormality caused by the static power test before the plant power is applied and the whole group is started. Reduce the dynamic test workload and test difficulty, to ensure that the dynamic test safety risk control and control in the state.
文摘With the rapid development of network technology and communication technology, all walks of life are moving towards the direction of intelligence, which has greatly promoted the social and economic progress in our country. The power industry is no exception. The emergence of smart substations has greatly improved some problems existing in the operation and maintenance of Chinas power industry and played a key role in promoting the long-term development of smart grids. More importantly, the relay protection technology has also been greatly changed under the support of the smart grid. Based on this background, strengthening the research work on the operation and maintenance of relay protection has an extremely far-reaching guiding role, which is helpful to promote the sustainable development of Chinas power grid construction.
文摘In the process of EFT / B immunity test, due to the influence of high frequency interference, the difference of test layout and test parameters may lead to the inconsistency of test results, thus affecting the reliability of each port test of relay protection device. This paper describes the possibility of uncertainty in each link of the test process, and analyzes the influence of reducing the uncertainty of EFT / B immunity test on the test results.
