Development of Digital Protective Relay Tester Under IEC61850
Development of Digital Protective Relay Tester Under IEC61850
Development of Digital Protective Relay Tester Under IEC61850
CHEN HuiCHEN Jiong-congLIANG Xiao-bingYU Nan-hua Electric Power Research Institute of Guangdong Power Grid Corporation Guangzhou 510080P.R. China E-MAIL:chenhui_jx@qq.com AbstractThe novel tester of digital protective relay based on
IEC61850 is proposed in this paper. The testers system architecture is based on multi-CPU(CPU+DSP) high speed hardware platform and real time operation system, it can receive and sample the analog test data on time, which is then converted into digital test data according to IEC61850 protocol. This tester also has the GOOSE trip signal which receive, the analysis digital protection device sends outand the circuit breaker position contact signal encoding, the group frame, transmits GOOSE the switch status to give the digitized relay protection installment and so on. The transient simulation testing platform is established, which can construct the electric quantity of each test cycle in the period of protections operation for sending under IEC61850. Due to the special recursive algorithm and detecting the action of protectionthe tester can complete the closed loop experiment of tripping-reclose-tripping forever. With the help of man machine interface, its very convenient to performance dynamic simulation test static simulation test and transient simulation test. This tester also get the fine results in the check of transient simulation test. converted internal by the optical fiber transmission to merge unit (MU), the merge unit do synchronous processing after the secondary side data collection from each optic-electronic transformer, group frame according to IEC61850-9, and transmit to new digital protective relay device through the optical fiber[9]~[11]. This tester will simulate all the operation from optic-electronic transformer to merge unit and from relay protection to intelligent switch, it includes the functions and characters as follows:1.It can receive multichannel analog signals(voltage and current), and group frame one by one according to IEC61850-9 which is transmitted to relay protection internal in real time[12]~[13].2.It has several digital input port and digital output port, the action signal from relay protection is transmitted to this tester in the form of GOOSE signal or digital output, then the tester transmits the signal to switch device in dynamic simulation laboratory or digital input in protection tester by its own digital output.3.With the internal simulation test platform, it can finish the closed loop experiment according to the chosen simulation fault module or fault situation[14]. This test system is base on the existing power system dynamic simulation experiment which consists of mature and widely used technology, relay protection static test and electro-magnetic transient simulation test, it makes traditional test methods play an important role in the new digital protection test, experiments and simulation analysis experiments.
1. Hardware design
This testers global design of hardware framework is shown in figure 1-1.
Dynamic simulation experiment transformer interface Protection device samples values input interface Protection device GOOSE information output interface Current and voltage converter AD sampling module
Optical fiber interface 1 Optical fiber interface 2
0. Introduction
In recent years, with the rapid development of integrated substation automation technology and communication technology, all kinds of unconventional optic-electronic measurement system gradually replaced electromagnetic mutual-inductance measurement systems. As the release of IEC61850 substation automation communication protocol, the realizing digitization in substation has become the future direction of substation automation technology development[1]~[4]. The use of digital protection will inevitable bring changes in corresponding test, testing equipment and testing methods. After adopting new digital protection devices, because of getting information and transmitting control commands in accord with the transmission IEC61850 statute of communication network, its different from traditional relay protection in test methods[5]~[8]. In order to ensure the safe and stable operation of digital substation, we need to research on test methods, means and standard, on this basis, and develop new protective relay tester. In the IEC61850 framework, the optic-electronic transformer of process level will transmit digital sample value which is
GPS module
Optic-electronic isolation
DSP
Optic-electronic isolation
dualport RAM
Management CPU
Humanmachine interface
1.1 Processor
Due to the high requirement of test system for real-time data processing, in order to realize the function of many complex tasks for a test device, the selection of the core processor hardware is crucial. This tester chooses the real-time system with combination of low-power CPU and DSP, CPU is mainly responsible for the management, man-machine interface and communication with DSP DSP has the strong data processing ability and high speed, and which is mainly responsible for data acquisition, encoding frame, sending and receiving GOOSE signals and communication with CPU. The data communication between CPU and DSP is mainly finished through dual-port RAM on DSP.
protocol in sampling value transmission model and GOOSE information model transmission. According to the demand function, this tester is determined specific software and hardware configurations after its function division. The management CPU runs on the Windows2000 operation system which is famous with stability, using Microsoft Visual c + + development environment, the human-machine interface management software is developed which embeds simulation experiment function and communication function with DSP, and realizes data management and analysis in the experiment or after the experiment. The DSP runs on the small famous real time operation system- C/OS, due to the different priorities in task and the real-time dispatch in management CPU, it can finish all the tasks consequence in proper sequence. The management CPU and DSP work in the form of principal and subordinate style on the whole, management CPU is principal and DSP is subordinate, executing task and obtaining parameters have to get the commands from management CPU at any time, if DSP need to upload data forwardly, it has to send notice signals to management CPU, and the management CPU will check DSP whether there is command to deal with.
Sw
Analog signals of voltage and current The interface from dynamic simulation experiment or relay protection testing system
2 Design thinking
This digital protective relay tester mainly consists of two important functions: analog experiment and simulation experiment, it also includes management and analysis modules of experiment data. There functions depend on the realization of IEC61850
er al fib optic message SE (GOO ission) transm er al fib optic g value plin on) (sam smissi tran
be connected for an APDU. The frame format of APDU is shown in figure 2-3.
APCIApplication Protocol Control Information ASDUApplication Service Data Unit
Tag
Length
ASDU number ASDU1 ASDU2 3 Fig.2-3 The APDU frame format of tester
ASDU3
1. 2.
Reclose
3.
Trip forever
4.
Fault,Trip,Reclose,Trip forver
Considering the ease-ofuse for user operation, several kinds of conventional pre-set system models are provided for users to choose, such as line fault and transformer fault model. Meanwhile, considering the user-opening in simulation experiment, this simulation platform also provides all the simulation software interface for user operation and management, if users define breaker node according to prescribed format, then a complex system model with their own need is built freely and put into normal operation.
state(waiting for event to occur), and interrupted state. The conversion relationship among 5 states is shown in figure 2-4. C/Os can manage 64 tasks, and 56 tasks can be used by users. Each task priority must be different, on the condition of ready state, C/OS always run the highest priority task, 0 for the highest, and 63 for the lowest.
is Task d e ncell ca Resuming task
Registering task Canceling task Task is cancelled
hang-up state
waitting Getting CPU permission Depriving permission
dormancy state
ready state
running state
interrupt interrupt
ed state
Interrupt stop
2.85 2.54
According to the functional need analysis, two system tasks, and three user tasks are set. (1) "Watchdog" task: This is the highest priority task in system level, its also the highest priority task in the entire system, setting priority 5. To ensure the stable operation of the system, the system feed the dog timely, if suddenness occurs, "watchdog" program will send a reset signal to the system. (2) GOOSE signal received task: another system level task, setting priority 6. Received from the network interfaces for GOOSE signals and delivered to the user task 2 through the message queue. (3) User task1: it checks and verifies the command from the management CPU in the dual-port RAM, the priority level is set to 16, and its delivered to user task3 through message queue, then informs user task3 download data from dual-port RAM. (4) User task2: GOOSE signals is received from the message queue to analyze and output through output port. Its priority is set to 17. (5) User task3: it downloads and uploads data from dual-port RAM, its priority is set to 18. Each task transferring relationship is shown in figure 2-5.
2.85
2.54
Fig.3-1 The phase current and voltage waveform describing Protection tripping without reclosing
Watchdog
Downloading and uploading data from dual-port RAM
Fig.3-2 The phase current and voltage waveform describing Protection tripping with reclosing
GOOSE received
Checking and verifying data from dual-port RAM
[7] [8]
Fig.3-3 The phase current and voltage waveform describing Protection tripping with reclosing, then tripping forever
These waveforms tell that the transient simulation experiment function can complete closed-loop transient simulation testing on digital protection successfully.
4 Conclusions
The emergence of IEC61850 to realizes interoperability between relay protection of different manufacturers, so that more and more Digital protection based on optical fiber communication gradually replaced traditional protection devices. Periodic testing on relay protection will play an extremely important role to ensure the safe operation of power system, however, the traditional relay protection is impossible to complete the testing mission for digital relay protection. To establish a digital protective relay tester which suits new digital protection and inherits the traditional testing method is important to ensure reliable action on digital protection and comprehensive promotion of digital substation. The tester based on IEC61850 protocol, with two functions of analog experiment and transient closed-loop simulation experiment, and can conduct a comprehensive digital test on digital protection. After being tested and used , it can meet using requirement in worksite well. [12] [13] [14]
[15]
Equipment, 2008, 28(6):111-114 FAN Chen, CHEN Xiao-chuan. Application of XML Schema in substation IED configuration[J], Electric Power Automation Equipment, 2007, 27(3):120-123 WU Zai-jun, HU Min-qiang. Analysis of IEC61850-communication networks and system in substations[J], Electric Power Automation Equipment, 2002, 22(11): 70-72 XU Bin, LIU Zi-ying, Design of IED based on IEC61850 standard for distribution system line protection[J], Electric Power Automation Equipment, 2007, 27(9):103-106 XU Ke1, WU Zai-jun, MIN Tao, et. Digital protection platform based on IEC 61850[J], Electric Power Automation Equipment, 2007, 27(2):79-84 ZENG Cheng; shan1, HE Hai, jun, XIE Pei yuan, et. Product platform for microcomputer protection system based on C/OS-II and DSP[J], Electric Power Automation Equipment, 2005, 25(7):57-60 FENG Shuo, HUANG Mei, LI Xiao-peng. Development of fiber digital relay protection tester based on IEC61850[J].Relay,2008, 36(8):23-25 ZHAO Shun-lin. Researching and Simulation of Computer Relay Protection Testing Device[D], Thesis of Master Degree from Shichuan University. 2006. DOU Xiao-bo, WU Zai-jun, HU Min-qiang. Information Model and Mapping Implementation of Merging Unit Based on IEC61850[J],.Power System Technology, 2006, 30(2):80-86 Jean J. Labrosse. C/OS-II The Real-Time Kernel, Second Edition, CMP Books.
Biography
CHEN Hui(1985-) male JiangXi Nanchang Han Master main the research directions for the Power System and its Automation Email:chenhui_jx@qq.com CHEN Jiong-cong(1979-) male GuangXi Wuzhou Han Master the main research directions for the Power System and its AutomationEmail:chenjiongcong@gddky.csg.cn LIANG Xiao-bing(1973-)maleHeBei TangshanHanMaster the main research directions for the Power System and its AutomationEmail:liangxiaobing@gddky.csg.cn YU Nan-hua(1976-) male JiangXi Jiujiang Han Doctor main the research directions for the Power System and its Automation Email:yunanhua@gddky.csg.cn
References
[1] [2] XU Ning, ZHU Yongli, DI Jian,et al. Substation automation object modeling based on IEC61850[J]. Electric Power Automation Equipment, 2006, 26(3):85-89. DOU Xiao-bo, TAO Hong-ping, HU Min-qiang, et. Design and realization of IEC-61850 configuration tool based on C#.NET[J], Electric Power Automation Equipment, 2007, 27(11):67-70. BIAN Peng, PAN Zhen-cun, GAO Zhan-jun, et. Application of SCL in remote substation configuration management[J], Electric Power Automation Equipment, 2004, 24(4):54-56 DENG Peng, YOU Da-hai, WANG Jian, WANG Yang-guang, et. MMS-based communication between IEDs and substation or dispatch center[J], Electric Power Automation Equipment, 2005, 25(11):62-65 GONG Jun-qiang, HUANG Yi-zhuang, XIA Ming-chao. Application of MMS in IEDs of power system[J], Electric Power Automation Equipment, 2004, 24(6):72-75 HUANG Weisong, GE Hui. Application of file transfer model defined in IEC61850[J], Electric Power Automation
[3] [4]
[5] [6]