利用系數(shù)法確定計(jì)算負(fù)荷（Word）

1、5.2.5 利用系數(shù)法確定計(jì)算負(fù)荷用利用系數(shù)法確定計(jì)算負(fù)荷時(shí)，不論計(jì)算范圍大小，都必須求出該計(jì)算范圍內(nèi)用電設(shè)備有效臺(tái)數(shù)及最大系數(shù)，而后算出結(jié)果。（1）用電設(shè)備組在最大負(fù)荷班內(nèi)的平均負(fù)荷：有功功率 kW（5-2-12）無功功率 kvar（5-2-13）式中 用電設(shè)備組的設(shè)備功率，kW；用電設(shè)備組在最大負(fù)荷班內(nèi)的利用系數(shù)，見表5-2-6；用電設(shè)備組的功率因數(shù)角的正切值，見表5-2-6。表5-2-6 利用系數(shù)、及用電設(shè)備組名稱一般工作制小批生產(chǎn)用金屬切削機(jī)床（小型車、刨、插、銑、鉆床、砂輪機(jī)等）0.10.120.501.73一般工作制大批生產(chǎn)用金屬切削機(jī)床0.120.140.501.73重工作制金屬

2、切削機(jī)床（沖床、自動(dòng)車床、六角車床、粗磨、銑齒、大型車床、刨、銑、立車、鏜床）0.160.551.51小批生產(chǎn)金屬熱加工機(jī)床（鍛錘傳動(dòng)裝置、鍛造機(jī)、拉絲機(jī)、清理轉(zhuǎn)磨筒、碾磨機(jī)等）0.170.601.33大批生產(chǎn)金屬熱加工機(jī)床0.200.651.17生產(chǎn)用通風(fēng)機(jī)0.550.800.75衛(wèi)生用通風(fēng)機(jī)0.500.800.75泵、空氣壓縮機(jī)、電動(dòng)發(fā)電機(jī)組0.550.800.75移動(dòng)式電動(dòng)工具0.050.501.73不聯(lián)鎖的連續(xù)運(yùn)輸機(jī)械（提升機(jī)、皮帶運(yùn)輸機(jī)、螺旋運(yùn)輸機(jī)等）0.350.750.88聯(lián)鎖的連續(xù)運(yùn)輸機(jī)械0.500.750.88起重機(jī)及電動(dòng)葫蘆（=100%）0.150.200.501.73電阻爐

3、、干燥箱、加熱設(shè)備0.550.650.950.33試驗(yàn)室用小型電熱設(shè)備0.351.000.0010t以下電弧煉鋼爐0.650.800.752 / 10單頭直流弧焊機(jī)0.250.601.33多頭直流弧焊機(jī)0.500.701.02單頭弧焊變壓器0.250.352.67多頭弧焊變壓器0.300.352.67自動(dòng)弧焊機(jī)0.300.501.73點(diǎn)焊機(jī)及縫焊機(jī)0.250.601.33對(duì)焊機(jī)及鉚釘加熱器0.250.701.02工頻感應(yīng)電爐0.750.352.67高頻感應(yīng)電爐（用電動(dòng)發(fā)電機(jī)組）0.700.800.75高頻感應(yīng)電爐（用真空管振蕩器）0.650.651.17（2）平均利用系數(shù)為（5-2-14）式中

4、 各用電設(shè)備組平均負(fù)荷的有功功率之和，kW；各用電設(shè)備組的設(shè)備功率之和，kW。（3）用電設(shè)備的有效臺(tái)數(shù)是將不同設(shè)備功率和工作制的用電設(shè)備臺(tái)數(shù)換算為相同設(shè)備功率和工作制的有效值。故（5-2-15）式中 單個(gè)用電設(shè)備的設(shè)備功率，kW。1）當(dāng)有效臺(tái)數(shù)為4臺(tái)及以上，且最大一臺(tái)設(shè)備功率與最小一臺(tái)設(shè)備功率的比值m3時(shí)，?。?-2-16）在確定值時(shí)，可將組內(nèi)總功率不超過全組總設(shè)備功率5%的一些最小用電設(shè)備略去。2）當(dāng)3和0.2時(shí)，?。?-2-17）如按上式求得的比實(shí)際臺(tái)數(shù)還多，則取。3）當(dāng)3和0.2時(shí)，?。?-2-18）（5-2-19）（5-2-20）以上式中用電設(shè)備臺(tái)數(shù)；用電設(shè)備中，單臺(tái)設(shè)備功率不小于最大

5、一臺(tái)設(shè)備功率一半的臺(tái)數(shù)；臺(tái)數(shù)的相對(duì)值；各用電設(shè)備組的設(shè)備功率之和，kW；臺(tái)設(shè)備的總設(shè)備功率，kW；功率的相對(duì)值；有效臺(tái)數(shù)相對(duì)值，可根據(jù)相對(duì)值和，從表5-2-7查得。表5-2-7 用電設(shè)備有效臺(tái)數(shù)相對(duì)值1.00.950.90.850.80.750.70.650.60.550.50.450.40.350.30.250.20.150.10.010.010.010.010.010.020.020.020.020.030.030.040.050.060.080.100.140.200.320.520.020.020.020.020.030.030.030.040.040.050.060.070.090.

6、110.140.190.260.360.510.710.030.030.030.030.040.040.050.060.070.080.080.110.130.160.210.270.360.490.640.810.040.040.040.040.050.060.070.080.090.100.120.150.180.220.270.340.440.570.720.860.050.050.050.060.070.070.080.100.110.130.150.180.220.260.330.410.510.640.790.900.060.060.060.070.080.090.100.120.

7、130.150.180.210.260.310.380.470.580.700.830.920.080.080.080.090.110.120.130.150.170.200.240.280.330.400.480.570.680.790.890.940.100.090.100.120.130.150.170.190.220.250.290.340.400.470.560.660.760.850.920.950.150.140.160.170.200.230.250.280.320.370.420.480.560.670.720.800.880.930.950.200.190.210.230.

8、260.290.330.370.420.470.540.640.690.760.830.890.930.950.250.240.260.290.320.360.410.450.510.570.640.710.780.850.900.930.950.300.290.320.350.390.430.480.530.600.660.730.800.860.900.940.950.350.330.370.410.450.500.560.620.680.740.810.860.910.940.950.400.380.420.470.520.570.630.690.750.810.860.910.930.

9、950.450.430.470.520.580.640.700.760.810.870.910.930.950.500.480.530.580.640.700.760.820.870.910.940.550.550.520.570.630.690.750.820.870.910.940.950.600.570.630.690.750.810.870.910.940.950.650.620.680.740.810.860.910.940.950.700.660.730.800.860.900.940.950.750.710.780.850.900.930.950.800.760.830.890.

10、940.950.850.800.880.930.950.900.850.920.951.000.95（4）計(jì)算負(fù)荷及計(jì)算電流：有功功率 kW（5-2-21）無功功率 kvar（5-2-22）視在功率, kVA（5-2-23）計(jì)算電流, A（5-2-24）式中 額定電壓，kV；最大系數(shù) 表5-2-8的Km數(shù)據(jù)是按0.5h最大負(fù)荷計(jì)算的。計(jì)算以中小截面導(dǎo)線為基準(zhǔn)，其發(fā)熱時(shí)間常數(shù)為10min，負(fù)荷的熱效應(yīng)達(dá)到穩(wěn)態(tài)的持續(xù)時(shí)間t，按指數(shù)曲線約為3，即0.5h。對(duì)于變電所低壓母線或低壓干線來說，20min，t1h。當(dāng)t0.5h，最大系數(shù)按下式換算，根據(jù)有效臺(tái)數(shù)和平均利用系數(shù)，從表5-2-8查得。表5-2-

11、8 最大系數(shù)0.10.150.20.30.40.50.60.70.80.943.433.112.642.141.871.651.461.291.141.0553.232.872.422.001.761.571.411.261.121.0463.042.642.241.881.661.511.371.231.101.0472.882.482.101.081.581.451.331.211.091.0482.722.311.991.721.521.401.301.201.081.0492.562.201.901.651.471.371.281.181.081.03102.422.101.841.6

12、01.431.341.261.161.071.03122.241.961.751.521.361.281.231.151.071.03142.101.851.671.451.321.251.201.131.071.03161.991.771.611.411.281.231.181.121.071.03181.911.701.551.371.261.211.161.111.061.03201.841.651.501.341.241.201.151.111.061.03251.711.551.401.281.211.171.141.101.061.03301.621.461.341.241.191

13、.161.131.101.051.03351.561.411.301.211.171.151.121.091.051.02401.501.371.271.191.151.131.121.091.051.02451.451.331.251.171.141.121.111.081.041.02501.401.301.231.161.141.111.101.081.041.02601.321.251.191.141.121.111.091.071.031.02701.271.221.171.121.101.101.091.061.031.02801.251.201.151.111.101.101.081.061.031.02901.231.181.131.101.091.091.081.051.021.021001.211.171.121.101.081.081.071.051.021.021201.191.161.121.091.071.071.071.051.051.021601.161.131.101.081.051.051.051.041.021.022001.151.121.091.071.051.051.051.041.011.012401.141.111.081.071.051.051.051.031.011.01其他符號(hào)含義同上。3臺(tái)及以下用電設(shè)備的