Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Shortening the Time of High-voltage Circuit Breaker Preventive Test of 110 kV and Above Chen Yifeng QC group Jiangmen Xinhui Power Supply Bureau, Guangdong Power Grid Company, China PREFACE Xinhui Power Bureau is a medium-sized state-owned power supply enterprise which subordinates to Guangdong Power Grid. Up to the early of 2008, it had 28 substations, including four 220 KV substations, twenty-four 110 KV ones. And the high-voltage circuit breaker is the one of the most important electrical equipments which controls the power supply . Therefor , we must test it every year, and we want to complete the test in a shorter time. We found some methods which can reduce the testing time as well as the danger of job by doing a great deal of research, at the same time , to improve the whole working efficiency. I. Group Profile High-voltage test unit of Xinhui Power Bureau is responsible for all the test of substations’ high-voltage equipment. There were twelve members in our QC group , all of them are good at doing the testing job. And our QC group is devoted to improving the work efficiency and guaranteeing the quality. Table 1 Registration form of group members Group name Group type Chen Yifeng QC group Gour Task name Scene type Shortening the Time of High-voltage Circuit Breaker Preventive Test of 110 kV and Above Activity number 11 Activity date Registration times Sep. 21st, 2007 Date Registration 2007.07.21 -2008.02.29 NO: 07A-02 number TQC Name Gender Age Level Title education time (h) Working Distribution in the group Chen Yifeng Male 44 Technical secondary school Monitor 108 Director Chen Zihui Male 32 Undergraduate course Monitor 108 Organizer Yu Zhiwei Male 26 Undergraduate course Vice Monitor 90 Trimmer Liang Jianxin Male 41 Technical secondary school Member 80 Executant Wan Liju Male 44 Technical secondary school Member 88 Examiner Deng Zhiqiang Male 33 Technical secondary school Member 86 Executant Zhu Yaohui Male 26 Junior college Member 90 Examiner Lin Meilian Female 43 Technical secondary school Member 90 Executant Sun Xiuzhen Female 49 Senior high school Member 80 Executant Li Xianming Female 34 Junior college Member 80 Executant Zhang Yuetian Male 24 Technical secondary school Member 80 Executant Tang Minghua Male 25 Undergraduate course Member 80 Examiner Lister:Yu Zhiwei NO. 0 Sheeting date:2008.02.28 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group II. The reason of Selection of Title In order to ensure the normal power supply , we must do high-voltage equipments preventive test every year. Ensuring normal power supply so that to reduce power cuts Demands of power supply time and load loss The test should be finished as soon as possible to ensure Demands of department the time of power supply and safety. The test interval of high-voltage circuit breaker 110 Difficulties encountered kV or over is long and the progress is slow: for 4 persons have to execute breaker test to result in other tests have to be executed orderly so that operators complain. Time shaft Work grouping Operators 30-50min 60min-85min 40-55min 3 persons test 4 persons test CT PT / Permit High voltage test 30-40min Waiting 4 persons test Breaker group The time of test confirme restart power Relaying team and is very urgent. Waiting Protection test Rest Linkage test 110 kV and above high voltage circuit breaker test ,with lots of difficulty and time wasting , person number and time occupy the most of part of the whole test progress (they are 66% and 40%) is main matter to impact the progress of the whole test. Shortening the Time of High-voltage Circuit Breaker Preventive Test of 110 kV and Above Fig I Argumentation chart of selection of title Mapper: Yu Zhiwei Listing date: 2008.02.28 NO. 1 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group III. Mastering Actuality: 1. In the testing period of 2007 , our QC group took sample tests in some of the high voltage circuit breaker in 28 substation , and got statistic as below: Table 2 Statistic questionnaire of time of high voltage circuit breaker of every substation Rank of breaker Statistic Average consumption time of the voltage number test(min) 1 220kV 4 112 2006.11-12 2 110kV 25 84 2006.10-2007.06 3 35kV 1 22 2007.01 4 10kV 32 18 Item No. Test date 2006.12-2007.05 Lister: Yu Zhiwei Listing date: 2008.02.28 2. QC group found the consumption of the test of high voltage circuit breaker of rank voltage 110 kV and above is the longest according to the statistic , but our bureau is mainly to test rank voltage 110 kV, therefore the testing time of 110 kV high voltage circuit breaker is analyzed mainly here. The member of our QC group took a simple working flow for a latest test of high voltage circuit breaker firstly so that it is convenient to evaluate a whole flow for every part of the test: Start 2(min) The explanation at scene and arrange the workers preparation before test The consumption time of time of test of C/O coil The consumption working 2(min) Meters, equipments which need and tools necessary before start working 2(min) The equipments will be arranged at Checking relative scene, power supply will be connected nameplates of breakers The connection of voltage 3(min) test of C/O coil 2(min) Test of C/O coil 2(min) 14(min) Re-arrangement and changing test meters and tidy last test meters The connection of contact resistance test of breaker NO. 2 2 (min) Shortening the time of high voltage circuit breaker preventive test 110 kV and above 35.5(min) The consumption time of test of contact resistance 5(min) 13(min) 5(min) A-phase contact resistance test of breaker Changing the connection to B-phase The test of B-phase contact resistance 13.5(min) Changing the connection to C-phase 5(min) The test of C-phase contact resistance 1(min) Record and analysis of the test date 3(min) 2.5(min) The consumption time of test of SF6 3(min) 1(min) Chen Yifeng QC group Tidy meters and changing the meters of next test The connection of SF6 test Test of SF6 Record and analysis of the test date Recovering connection and checking 1(min) whether gas leaks The consumption time of recovering after test 3(min) Checking and accepting high voltage circuit breaker and reclaim tools and meters The end Fig 2 Test working flow Mapper: Yu Zhiwei Listing date: 2008.02.28 According to the order of test flow chart, we got the consumption time of every test and make the statistics of 25 tests as following: (the time of changing equipments for next test has been computerized in the testing time) NO. 3 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Table 3 Statistics of every consumption time Item No. 1 Total time length(min) Average time length (min) Add up(%) Item name of test The time of preparing before test 153 6.12 07.25% 184.5 7.38 15.98% 1512.5 60.5 87.62% The time of test of operation voltage of 2 close/open coil 3 The time of test of contact resistance 4 The time of test of SF6 183 7.32 96.28% 5 The time of recovering after test 78.5 3.14 100% 2111.5(min) Total time length Average time length 84.46(min) Lister: Yu Zhiwei Listing date: 2008.02.28 Diagram of every consumption time had been made as statistics above Time length=84.46(min) Add up percentage (%) 80.37% 80 70 60.5 96.29% 89.04% 100 90 80 71.63% 60 70 50 60 40 50 40 30 30 20 7.38 10 7.32 6.12 N O . 4 N O . 1 20 3.14 0 N O . 3 N O . 2 10 0 N O . 5 Fig 3 Diagram of every consumption time of high-voltage circuit breaker Mapper: Yu Zhiwei Mapping date: 2008.02.28 We can see from the chart above: “The testing time of contact resistance of breaker” occupies 71.63% of the whole time of breaker test, and the time would be consumed longer while we carried out the 220 kV breaker contact resistance test . Therefore we had known clearly that we must reduce the testing time of contact resistance of breaker, it was the main link to shorten the time of breaker test. NO. 4 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group IV. The Objective The goal of QC activity for this time is that the average testing time of high voltage breaker can be reduced from 84.46(min) to 52(min) after this QC activity. The consumption of testing time: 84.46 (min) 52(min) Before QC activity Fig 4 Activity goal Goal sketch map of QC activity Mapper: Yu Zhiwei Mapping date: 2008.02.28 V. Feasible Analysis: Whole analysis: 1. Sometimes , we have spent the average time of 52(min) in doing the breaker test, and the fastest one was 44(min) by using scaffold or other platform which has been built and can be easy to do test at scene in the rebuilding project. 2. As we know, the time which be consumed in similar test conditions by the other test unit usually is within 52(min) , and the manufacturer has the advantages such as convenient position and advanced test platform, the time even can be reduced to 40 (min). Details analysis: 1.It didn’t take much time in test operation at all, but NO.2 8.74% more time is spent in the process of test. 2.We can see from the actual data which is NO.5 3.71% NO.4 8.67% investigated , the main time wasting part NO.1 7.25% is the contact resistance test. In the whole breaker test process, it occupied about 71.63% of the time, we estimated that the time could NO.3 71.63% be reduced by more than 10(min) If the time used in climbing up and down during test Chart 5 Analysis chart could be reduced more than 25(min) , Mapper : Yu Zhiwei Listing date: 2008.02.28 we would achieve our goal. We had found the key to attain the goal! All of this just show that the goal is achievable and feasible , our QC group can achieve the goal absolutely by our effort. NO. 5 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group VI. Reason Analysis Why did the test of contact resistance of breaker took so much time , we took part in many activities in a month in order to find out the answer . Through the survey, statistics and brainstorming, the QC group analyzed the main factors, and concluded the result to 4 aspects such as “person”, “machine”, “method” and “Environment”(There is nothing related to the factor “material” in our test, so we have not list it), which can be shown as follows: Technician Environment Ambiguous task distribution Inconvenient and unstable connection of mobile power supply Bad cooperation Doesn’t know the methods Influences among Manpower is not enough Lack of skill different jobs Inconvenient movement and Not familiar with equipments Abominable weather replacing equipment at scene Spent long time in the test of contact resistance Disrepair tools No output from equipment The wrong ways of breaker The tools which test Bug of equipment needs are not on deck Bad screen of equipment Equipment Wrong test connection Backward measure method Losing tools Method Inconvenient connection Inconvenient measure Fig 6 Analysis chart of cause and effect of long testing time of contact resistance of breaker Mapper: Yu Zhiwei NO. 6 Mapping date: 2008.02.28 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group VII. Reasoning on The Main Causes Which one is the main cause, all members were earnest to study, argue one after another , as indicated in the following table. Table 4 Argumentation of key factors Item Factors No. Argumentation Descriptions Checker Ambiguous 1 task The works will be arranged in the daily meeting before every job. distribution Manpower 2 is not enough 3 Our department and unit both paid much attention to training, all the testing workers had passed the examinations with high level before they methods performed praitical test jobing. with No output of equipment Examination results showed that all the test workers are familiar with the of 8 Disrepair tools Losing tools Zhang Yuetian Zhu Yaohui We kept doing maintainance periodically. The defect rates of the testing Liang equipment was totally 0%. Jianxin We check the result display before every job so that it can work precisely. equipment 7 Deng operation of testing equipment. Bad screen 6 Yifeng Zhiqiang Doesn’t equipments 5 workers . know the Not familiar 4 Through all the test,we seldom failed the job to the lack of testing Chen Liang Jianxin Li All tools are 100% up to standard. Xianming Tools, equipments and meters have been checked before we set out. Chen Yifeng Checking Main Date Cause 2007.07.05 No 2007.07.05 No 2007.07.05 No 2007.07.05 No 2007.07.12 No 2007.07.12 No 2007.07.12 No 2007.07.12 No 2007.07.19 No 2007.07.19 No 1、Because the test area is far from the connection site, and it took 2-4(min) to lay power wire in high -voltage site . 2、According to the statistic, the probability of wrong turning off power Inconvenient and unstable connection 9 of mobile power supply reached 40% if many plug were connected to the same power socket. See the statistics: Shuang Test Dian line I line Turn off 5 power number Error 2 number Time 4 (min) Yinjin line Yigang line Neng Shuang line Xinjin line Yu Zhiwei 4 3 5 3 1 0 1 0 3 2 3 2 Influences 10 among This situation seldom took place during the preventive test, because we Yu different can cooperate with the members of relaying protection team very well. Zhiwei jobs NO. 7 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Abominable 11 weather Chen Yifeng QC group Weather is the most important influence factor during the preventive test , so we don’t start our test in a bad weather. Sun Xiuzhen 2007.07.19 No 2007.07.19 Yes 2007.07.30 No 2007.07.30 Yes 2007.07.30 No 2007.07.30 Yes Mis-arrangement usually happened which disturb changing meters or equipments, 12 and impacting mood .According to the Inconvenient investigation, 80% workers considerd they fell into a bad mood and work movement with low efficiency when they encountered such situation. and See the statistics: replacing Tang Test line equipment at scene Shuang Dian I line Yinjin line Yigang line Neng Shuang line Xinjin line 6 5 5 6 4 4 4 5 5 3 Investigated number Bad appraisement 13 working The wrong way The test method has been recognized by technical department. Minghua Wan liju 1、The breaker of 110 kV, in particular 220 kV is located very high, common insulation ladder can not reach suitable height, at least over 13-grade ladder must be taken, so it need more than 2-4 persons to carry the ladder; 2、The test workers need to work at high altitude so it is very difficult and dangerous; 14 Inconvenient 3、For the test connection, the test workers have to climb down and move Chen connection to another phase breaker again after finished one phase test, and the Zihui difficult process consumed nearly 40.8(min). See the statistics: One-line Test double-power line Person Time (min) 15 Yinjin line Yigang line Xinjin line 2 Neng Shuang line 4 3 3 40 40 46 40 38 4 Wrong test Clear mark of test line, and simple connection, therefore the wrong test Chen connection connection will not happened. Zihui In order to get exact result, we need to use multimeter to measure voltage, and we had to climb up and down so the time had to be consumed 15 (min) 16 Inconvenient measure See the statistics: Shuang Test Dian line I line Time 14 (min) Wan Liju Yinjin line Yigang line 15 14 Neng Shuang line 17 Xinjin line 15 Lister: Yu Zhiwei Listing date: 2008.02.28 We got 4 key factors as the argumentation of key factor in table 4: ★Inconvenient connection ★Inconvenient movement and replacing equipment at scene measure ★Inconvenient and unstable connection of mobile power supply NO. 8 ★Inconvenient Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group VIII. Making Countermeasures We studied countermeasures as argumentation table of key factors of ratio brake idiocratic , as following: Table 5 Item Factor No. 1 Methods Inconvenient Use tool to avoid connection climbing replacing 2 equipment at Standardization putting Shorten 50% of test connection time build happy working suitable Complete date long handle tools to avoid workers Chen Yifeng 2007.11.20 climbing up and down. will be used one after another in Yu Zhiwei 2007.09.11 so that the workers don’t climb Chen Zihui 2007.12.24 reached Looking for new Shorten 50% of test measure measure means measure time definite mark of connection of power supply and mobile power distribute persons supply for environment so that 80% of the appointed area keep the Inconvenient and unstable Looking Principal the good appraisement can be space of walking and turning. Inconvenient Designing a kind of 4 Measures meters and transfer direction, Puting test equipments which scene 3 Goal Be convenient to change Inconvenient movement and Countermeasure to inspect Looking for long measure pole up to do measureing 1.Team No. will be stick on the Reduce 50% of time of plugs of power; identification of power 2.Avoid the line of power to supply, and the number of be layed in busy area; plug out error is 0. Lin Meilian 2007.10.10 3. Appoint the special person to inspect if no any methods. Lister: Yu Zhiwei Listing date: 2008.02.28 IX. Taking Countermeasures Measure 1: using tool to avoid climbing (Appointed Chen Yifeng, Deng Zhiqiang and Tang Minghua on November 20 th, 2007) ◆The methods we usually take is to clamp the lines by two ends of high voltage connection board of breaker, insulation ladder with more than 13 grades will be needed so that the ladder is heavy enough , it needs two persons at least to carry it, moreover clamping at high altitude is very dangerous, as follow: NO. 9 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group If there were any tools which could stretch to clamp the high voltage connection board, then we didn’t need to climb up to connect the test lines, furthermore our company’s safety regulations to avoid climbing the breaker . Are there any tools suitable for the demands? We paid our attention to the ground rod, used the clamp of the ground rod to fix high voltage connection board, utilized ground wire to output current flow, thus to avoid workers climbing up . However , it is inconvenient to carry the ground wire since they’re too heavy . And on the other hand , it took time and hard force to tighten the clamp. In order to make the job more convenient , we searched method from every aspects . We had tried to discuss with the high voltage equipment manufacturers. And finally we found out a very useful clamp which fully meets our need in a manufacturer in Beijing. NO. 10 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group The picture above is the high altitude clamp which is ready; in the next picture it shows the design of the clamp sub. It is so light and convenient and can reduce our working difficulty by using this high altitude clamp: NO. 11 Shortening the time of high voltage circuit breaker preventive test 110 kV and above NO. 12 Chen Yifeng QC group Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Checking execution result: Table 6 Result checking sheet after execution Before execution After execution Effect Person number 4 2 Reduce 50% Time(min) Finish or not 40.8 7 Decline 83%>50% Yes Lister: Chen Yifeng Listing date: 2007.11.21 In this way, not only our work become easier and safer, but we could carry out by less workers so that the whole working progress of preventive test could be improved. Table 7 Result checking sheet after execution Time shaft Operators High voltage test team Allowed Relaying team Waiting Waiting Time flow of Two persons execute breaker test once Three persons execute test CT once Protection test Rest Four persons execute test PT once less a test item than before! Linkage test Lister: Chen Yifeng Listing date: 2007.11.21 Measure 2: Standardization putting tools (Yu Zhiwei, Zhu Yaohui and Zhang Yuetian were appointed on Nov.9 th, 2007) ◆The test meters are put in the area which is appointed orderly, so that we can easily fetch them and put them back. The testing line should be orderly placed without any cross or knots. We failed to appreciate significance of working environment before, we put the tools at will so that it not only blocks working but also affects other’s movement. NO. 13 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group There has been complete different result at our working site after we took measures , we can work and move with enough space , all of this make us fall into a good mood ,and it increases our work efficiency. Checking execution result: Table 8 Result checking sheet after execution Respondents list Appraised score before execution Appraised score after execution Working mood Wan Zhu Zhang Li Yao Yue ju hui tian Chen Yi feng Chen Zi hui Yu Zhi wei Liang Jian Xin Deng Zhi qiang 3 4 4 6 4 5 3 2 8 9 8 8 9 9 8 9 Finish or not Ratio Lin Mei lian Sun Xiu zhen Li Xian ming Tang Ming hua 3 4 3 4 8 9 9 9 83% bad appraisement 100% good appraisement Yes Lister: Yu Zhiwei Listing date: 2007.09.11 (Note: Bad is 0-4 score, middle is 5-7 score, good is 8-10 score) Measure 3: Modify measure means (Chen Zihui, Wan Liju and Liang Jianxin were appointed on Dec. 24 th, 2007) ◆At first , we used the high altitude clamp to avoid workers climb the high position for measuring contact resistance by using multimeter , it did save much time and ensure safety, but there was a matter that the clamp sub is too big to clamp the right measuring position, then it limited the choice of measuring point so that the error of contact resistance is probably increased . It would be all right if we had lengthen multimeter-pen. For this, we have observed ground rod. NO. 14 Shortening the time of high voltage circuit breaker preventive test 110 kV and above At first , We got a piece of “long-pole” after we took the clamp sub of ground rod apart: NO. 15 Chen Yifeng QC group Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group The metal head was too thick, we found a long wire, fixed one head of it by welding on the metal head of ground rod, the other head could be inserted into the multimeter , so we got our “long-pole-pen”. NO. 16 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group When we used the “long-pole-pen”, we found it was fast and convenient to measure and the value was so steady and accurate. NO. 17 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Checking execution result: Table 9 Result after execution Before execution After execution Respondents’ number 4 2 Reduce 50% Time(min) 15 6 Decline 60%>50% of goal Finish or not Result Yes Lister:Chen Zihui Listing date: 2007.12.25 Measure 4: designing a kind of definite mark of power supply, appoint persons to inspect (Lin Meilian, Sun Xiuzhen and Li Xianming were appointed on Oct. 10 th, 2007) ◆There were so many plugs of mobile power supply in a power board, furthermore , the wires of mobile power supply mixed together, and mobile power supply had to be moved frequently when we are working, all of these cases wasted much time in making out our plug, and usually, it was very easy to make a mistake. We gave numbers to every mobile power supply, we stuck ID labels on every plug of mobile power supply, therefore we could pull out the plug without any mistakes. NO. 18 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group As the actuality at scene, if we had to put the wire of power supply in the busy area, we would appoint a person to watch. Checking execution result: Table 10 Result checking after execution Error rate Time(min) Finish or not Before execution After execution 20% 2-4 0% 0-1 Yes Result Reduce 20% Decline 50%= 50% of goal Lister: Lin Meilian Listing date: 2007.10.11 IX. Check Result: According to the statistics , we found that it achieve good results by executing every measure: 1. Workers don’t need to climb insulation post to clamp the holding wire after we adopted high altitude clamp as current output tool, they can operate on the ground, therefore the average time to clamp lines has reduced 33 (min) at all; 2. There is a good order at test scene, it is not only convenient to work and we get a good mood, but also we found an excellent working environment which can help us to save 1 (min) during the whole test process of breaker. 3. The test workers didn’t need to climb up and down so that it ensure safety and economize testing time by nearly 9 (min) ,the measuring time of contact resistance of breaker is largely reduced and it becomes one of our fastest and easiest tests. 4. The error rate of which we putting out the plug is reduced much by using labels so that we saved 2 (min) during the whole process. We took tests of 110 kV high voltage breaker at Da’ao substation on Jan.12th, 2008, and at Tongguan substation on Feb. 29th, 2008 by using the new tools and measures, and we got satisfying results: See the following statistics: NO. 19 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Table 11 Statistics of test spending time after improving Item No. 1 2 Names of test items Da’ao substation Testing time(min) Muzhou Substation Testing time(min) Average time(min) 8.5 8.6 8.55 7.4 7.6 7.5 The time of preparing before test The time of test of operation voltage of close/open coil 3 The time of test of contact resistance 15 14 14.5 4 The time of test of SF6 6.9 7.1 7.0 5 The time of recovering after test 4.0 3.8 3.9 Average total spending time 41.45(min) Lister: Yu Zhiwei Listing date: 2008.02.28 Through the following figure , we found the testing time of contact resistance has declined 35% in the whole consumption time, we believed this item had not been the main matter which influenced the consumption time of breaker test. Time length N=84.46(min) Add up percentage (%) 40 73.72% 30 20 100 90 80 70 60 50 40 30 20 10 0 90.61% 55.63% 14.5 35.00% 8.55 10 7.5 7 3.9 0 3 N O . 1 N O . 2 N O . N O . 4 5 N O . Figure 7 The sketch map of every spending time after improving Lister: Yu Zhiwei Listing date: 2008.02.28 With the exciting feelings, now we go back to look at our desired goal, our result was even lower than the target value, we succeeded. Test spending time 84.48(min) 52(min) 41.45 (min) Before QC activity Activity goal Fig 8 After QC activity Result sketch chart after improving NO. 20 Shortening the time of high voltage circuit breaker preventive test 110 kV and above Chen Yifeng QC group Mapper: Yu Zhiwei Mapping date: 2008.02.28 X. Social Benefit and Experience We found the method which can help us reduce testing time of high voltage breaker by investigation and discussion in this QC activity, in particular the testing time of contact resistance of 110 kV and 220 kV high voltage breaker, it not only reduced testing time but also economized manpower so that we finished the whole preventive test much faster, furthermore , it also ensured our workers safety. In this collaborative QC research, and following the PDCA procedures, all the team members have taken their initiatives and have coordinated and collaborated excellently; Meanwhile, the activity has also improved our technical competence and enhanced our team spirits. Table 12 Statistics of immaterial benefit of QC activity Skill level of team Cohesion of team Cooperation ability Knowledge QC exertion ability 70 75 73 72 75 91 98 93 90 90 Before activity After activity Skill level of team 100 活动前 活动后 50 QC exertion ability Cohesion of team 0 Knowledge Cooperation ability Figure 9 Analysis chart of immaterial benefit of QC activity Mapper: Yu Zhiwei Mapping date: 2008.02.28 XI. Consolidation Measures and Period We compiled Test Improving Report of High-voltage Circuit Breaker after we improved test method and process, which was approved by the leaders our department, and was incorporated into Test Manual of High-voltage Circuit Breaker, it was rapid to be acknowledged and extended by our brother team, some of the methods also work in other type of test. Then how to consolidate our achievement? At first, we should study and execute every rule regulated by our department, this is to ensure production and work safety and it is the base to promote work efficiency. Secondary, every new member must accept skill training in every aspect. They must master rules and skill so that they can improve and expert by themselves. The track record on the test consumption time of breaker in the succedent preventive test task after our team held the activity as following: Table 13 Statistics of test spending time of daily work after activity Item No. 1 Name of test item 110 kV Tongguan Substation, at 152 of Tongnan line Testing time(min) 8.30 The time of preparing before test NO. 21 Shortening the time of high voltage circuit breaker preventive test 110 kV and above 2 The time of test of operation voltage Chen Yifeng QC group 7.50 of close/open coil 3 The time of test of contact resistance 4 The time of test of SF6 7.1 5 The time of recovering after test 4.5 12.50 Total spending time 39..90 Lister: Yu Zhiwei Listing date: 2008.02.28 This shew that our achievement could be executed very well during the task, the realities proved our achievement was so effective, our endeavor was not wasted, we were happy that much time had been reduced. XII. Problem and Future plan Although we improved much during this QC activity, but we have to acknowledge that we still need to measure manually, the matter of precision error when measuring has not been settled, so we need to probe into the relative manufacturer. We didn’t hug ourselves on this achievement in this QC activity so that to stop our progress. As to the long consumption time in our preventive test and inefficient items, we will hold a new round of QC activity, Our intended title is “Improving Work Efficiency of Measuring Transformer winding”. NO. 22