HONEYWELL CC-TAID11工控模塊卡件
對(duì)于高于所述電壓的值，469將安全失速保護(hù)曲線外推至110%電壓。通過取100%電壓下的鎖定轉(zhuǎn)子電流并乘以1.10來計(jì)算該電流水平。對(duì)于超過110%電流水平的跳閘時(shí)間，將使用110%的跳閘時(shí)間。（見下圖）。圖4-10：電壓相關(guān)過載保護(hù)曲線安全失速曲線實(shí)際上是不同電壓下的一系列安全失速點(diǎn)。對(duì)于給定電壓，只有一個(gè)失速電流值，因此只有一個(gè)安全失速時(shí)間。1 123 456 78 2 3 4 5 6 7 8 9 10 20 30 40 50 60 80 90 100高慣性負(fù)載過載曲線8800 HP，13.2 kV，反應(yīng)堆冷卻劑泵跳閘時(shí)間（秒）滿載安培數(shù)200 300 400 500 600 700 800 900 1000加速相交于80%V自定義曲線加速相交于100%V 80%V安全失速時(shí)間，80%V失速電流安全失速時(shí)間，100%V失速電流安全失速點(diǎn)外推至110%V 806824A4.CDR GE Multilin注釋4-38 469電機(jī)管理繼電器GE Multilin 4.6 S5熱模型4設(shè)定值4以下兩個(gè)圖分別說明了80%和100%線路電壓的合成過載保護(hù)曲線。對(duì)于介于兩者之間的電壓，469將基于電機(jī)啟動(dòng)期間測(cè)得的線電壓線性且恒定地移動(dòng)加速度曲線。圖4–11：80%和100%電壓下的電壓相關(guān)過載保護(hù)d）不平衡偏置不平衡相電流也會(huì)導(dǎo)致額外的轉(zhuǎn)子發(fā)熱，機(jī)電繼電器和一些電子保護(hù)繼電器也不考慮。當(dāng)電機(jī)運(yùn)行時(shí)，轉(zhuǎn)子以接近同步的速度沿正序電流的方向旋轉(zhuǎn)。負(fù)序電流的相位旋轉(zhuǎn)與正序電流相反（因此，與轉(zhuǎn)子旋轉(zhuǎn)相反），產(chǎn)生轉(zhuǎn)子電壓，產(chǎn)生大量轉(zhuǎn)子電流。該感應(yīng)電流的頻率約為線路頻率的2倍：50Hz系統(tǒng)為100Hz，60Hz系統(tǒng)為120Hz。在該頻率下，轉(zhuǎn)子棒中的趨膚效應(yīng)導(dǎo)致轉(zhuǎn)子電阻顯著增加，因此轉(zhuǎn)子加熱顯著增加。電機(jī)制造商提供的熱極限曲線中未考慮這種額外的加熱，因?yàn)檫@些曲線僅假設(shè)電源和電機(jī)設(shè)計(jì)完全平衡的正序電流。469測(cè)量負(fù)序電流與正序電流的比率。熱模型可以被偏置以反映在電機(jī)運(yùn)行時(shí)由負(fù)序電流引起的額外加熱。這種偏置是通過創(chuàng)建等效的電機(jī)加熱電流而不是簡(jiǎn)單地使用平均電流（Iper_unit）來實(shí)現(xiàn)的。使用下面所示的公式計(jì)算該等效電流。1 123 456 78 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 90 100高慣性負(fù)載過載曲線8800 HP，13.2 kV，反應(yīng)堆冷卻劑泵跳閘時(shí)間（秒）滿載安培數(shù)200 300 400 500 600 700 800 900 1000 GE Multilin 806825A4.CDR 1 123 456 8 2 3 4 6 7 9 10 20 40 50 60 80 90 100高惰性負(fù)載過載曲線8600 HP，13.2kV，反應(yīng)堆冷卻劑泵跳閘時(shí)間（秒）多個(gè)滿載電流200 300 400 500 600 700 900 1000 GE Multilin 806826A4.CDR GE Multilin 469電機(jī)管理繼電器4-39 4設(shè)定值4.6 S5熱模型4（EQ 4.3）其中：Ieq=等效電機(jī)加熱電流Iper_unit=基于FLA的每單位電流I2=負(fù)序電流I1=正序電流k=常數(shù)以下顯示了NEMA（美國(guó)國(guó)家電氣制造商協(xié)會(huì)）推薦的根據(jù)電壓不平衡的推薦電機(jī)降額。假設(shè)典型的感應(yīng)電機(jī)具有6 x FLA的浪涌和0.167的負(fù)序阻抗，則1、2、3、4和5%的電壓不平衡相等
For values above the voltage in question, the 469 extrapolates the safe stall protection curve to 110% voltage. This current level is calculated by taking the locked rotor current at 100% voltage and multiplying by 1.10. For trip times above the 110% current level, the trip time of 110% will be used. (see figure below). Figure 4–10: VOLTAGE DEPENDENT OVERLOAD PROTECTION CURVES The safe stall curve is in reality a series of safe stall points for different voltages. For a given voltage, there can only be one value of stall current and therefore, only one safe stall time. 1 123 456 78 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90 100 HIGH INERTIA LOAD OVERLOAD CURVES 8800 HP, 13.2 kV, REACTOR COOLANT PUMP TIME TO TRIP (SECONDS) MULTIPLES OF FULL LOAD AMPS 200 300 400 500 600 700 800 900 1000 Acceleration Intersect at 80%V Custom Curve Acceleration Intersect at 100%V Safe Stall Time at 80%V, 80%V Stall Current Safe Stall Time at 100%V, 100%V Stall Current Safe Stall Points Extrapolated to 110%V 806824A4.CDR GE Multilin NOTE 4-38 469 Motor Management Relay GE Multilin 4.6 S5 THERMAL MODEL 4 SETPOINTS 4 The following two figures illustrate the resultant overload protection curves for 80% and 100% line voltage, respectively. For voltages in between, the 469 will shift the acceleration curve linearly and constantly based on measured line voltage during a motor start. Figure 4–11: VOLTAGE DEPENDENT OVERLOAD PROTECTION AT 80% AND 100% VOLTAGE d) UNBALANCE BIAS Unbalanced phase currents also cause additional rotor heating not accounted for by electromechanical relays and also not accounted for in some electronic protective relays. When the motor is running, the rotor rotates in the direction of the positive-sequence current at near synchronous speed. Negative-sequence current, with a phase rotation opposite to positivesequence current (and hence, opposite to the rotor rotation), generates a rotor voltage that produces a substantial rotor current. This induced current has a frequency approximately 2 times the line frequency: 100 Hz for a 50 Hz system or 120 Hz for a 60 Hz system. The skin effect in the rotor bars at this frequency causes a significant increase in rotor resistance and therefore a significant increase in rotor heating. This extra heating is not accounted for in the thermal limit curves supplied by the motor manufacturer, as these curves assume only positive-sequence currents from a perfectly balanced supply and motor design. The 469 measures the ratio of negative to positive-sequence current. The thermal model may be biased to reflect the additional heating that is caused by negative sequence current when the motor is running. This biasing is accomplished by creating an equivalent motor heating current rather than simply using average current (Iper_unit). This equivalent current is calculated using the equation shown below. 1 123 456 78 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90 100 HIGH INERTIA LOAD OVERLOAD CURVES 8800 HP, 13.2 kV, REACTOR COOLANT PUMP TIME TO TRIP (SECONDS) MULTIPLES OF FULL LOAD AMPS 200 300 400 500 600 700 800 900 1000 GE Multilin 806825A4.CDR 1 123 456 78 2 3 4 5 6 7 8 9 10 20 30 40 50 60 70 80 90 100 HIGH INERTIA LOAD OVERLOAD CURVES 8800 HP, 13.2 kV, REACTOR COOLANT PUMP TIME TO TRIP (SECONDS) MULTIPLES OF FULL LOAD AMPS 200 300 400 500 600 700 800 900 1000 GE Multilin 806826A4.CDR GE Multilin 469 Motor Management Relay 4-39 4 SETPOINTS 4.6 S5 THERMAL MODEL 4 (EQ 4.3) where: Ieq = equivalent motor heating current Iper_unit = per unit current based on FLA I2= negative sequence current I1= positive sequence current k = constant The figure below shows recommended motor derating as a function of voltage unbalance recommended by NEMA (the National Electrical Manufacturers Association). Assuming a typical induction motor with an inrush of 6 x FLA and a negative sequence impedance of 0.167, voltage unbalances of 1, 2, 3, 4, and 5% equal
