EPRO PR9268/307-100前置傳感器基于智能保護(hù)器RPC2701的礦用隔爆型真空饋電開關(guān)在煤礦井下三相中性點(diǎn)不接地的供電系統(tǒng)中，礦用隔爆型真空饋電開關(guān)可以作為井下配電系統(tǒng)的總開關(guān)或分支開關(guān)來(lái)使用，也可以作為大容量電動(dòng)機(jī)在不頻繁起動(dòng)時(shí)的控制裝置來(lái)使用。煤礦井下三相交流電的工作頻率為50Hz，額定電壓為660V或1140V，額定電流為50A至1000A。本文采用饋電開關(guān)專用智能保護(hù)器RPC2701作為礦用隔爆型真空饋電開關(guān)的保護(hù)器，滿足漏電保護(hù)裝置對(duì)快速性和穩(wěn)定性的要求，可以完成礦井低壓電網(wǎng)的二級(jí)選擇性漏電保護(hù)、對(duì)稱短路保護(hù)、不對(duì)稱短路保護(hù)、斷相保護(hù)、過(guò)載保護(hù)和過(guò)電壓保護(hù)等功能。
EPRO PR9268/307-100前置傳感器3.1 礦用隔爆型真空饋電開關(guān)的操作界面專用智能保護(hù)器RPC2701通過(guò)RS-232串行通訊口與觸摸屏HMI進(jìn)行通訊，并預(yù)留RS-485串行通訊口與上一級(jí)通訊分站進(jìn)行通訊。礦用隔爆型真空饋電開關(guān)的漏電保護(hù)系統(tǒng)由兩部分組成，其中一部分是基于附加直流檢測(cè)的總漏電保護(hù)系統(tǒng)，另外一部分是基于零序電流方向判斷的分支漏電保護(hù)系統(tǒng)。該漏電保護(hù)系統(tǒng)既可以完成井下低壓電網(wǎng)單相漏電時(shí)橫向選擇性和縱向選擇性功能，又能夠保證電網(wǎng)對(duì)稱漏電時(shí)保護(hù)動(dòng)作的穩(wěn)定性，使饋電開關(guān)既可靠又安全。礦用隔爆型真空饋電開關(guān)的電氣原理圖如圖3所示。 3.2.1 基于附加直流檢測(cè)的總漏電保護(hù)系統(tǒng)附加直流電源檢測(cè)式漏電保護(hù)原理示意圖如圖3所示，主要由三相電抗器及同步變壓器T3、零序電抗器及零序變壓器T2、電阻電容組成的濾波回路、直流電源組成。通過(guò)模塊RL通道附加的直流電源檢測(cè)電網(wǎng)對(duì)地絕緣電阻的變化。當(dāng)直流電壓一定時(shí)，檢測(cè)的電阻值變化。當(dāng)絕緣電阻下降到表1規(guī)定的動(dòng)作值時(shí)，PLC程序調(diào)用中斷進(jìn)行立即輸出，使繼電器動(dòng)作，其常開觸點(diǎn)接通饋電開關(guān)的分勵(lì)脫扣線圈，使開關(guān)跳閘，實(shí)現(xiàn)漏電保護(hù)，并通過(guò)液晶顯示屏將對(duì)地電阻值直觀地顯示出來(lái)。附加直流電源檢測(cè)式漏電保護(hù)系統(tǒng)具有保護(hù)全面和動(dòng)作無(wú)死區(qū)等優(yōu)點(diǎn)，但也具有動(dòng)作無(wú)選擇性和動(dòng)作時(shí)間長(zhǎng)等缺點(diǎn)。對(duì)于1140V等級(jí)，1K的漏電動(dòng)作時(shí)間不大于30ms。礦用低壓防爆饋電開關(guān)的選擇性漏電保護(hù)是指當(dāng)?shù)V井低壓電網(wǎng)某條支路的某一相發(fā)生人身觸電、或單相對(duì)地放電、或單相對(duì)地泄漏電流時(shí)，能及時(shí)檢測(cè)出漏電故障并作用于跳閘，有選擇性地只切斷故障線路，保證非故障線路安全運(yùn)行的保護(hù)設(shè)施。當(dāng)電網(wǎng)非對(duì)稱性漏電時(shí)，由取樣電路分別從電網(wǎng)中取出零序電壓U0和各支路的零序電流I0信號(hào)，如圖3所示，經(jīng)放大整形后，由相位比較電路來(lái)判斷故障支路，再判斷是否達(dá)到門檻值，最后啟動(dòng)執(zhí)行電路，切斷故障支路的電源，實(shí)現(xiàn)有選擇性的漏電保護(hù)。零序功率方向式選擇性漏電保護(hù)具有很強(qiáng)的橫向選擇性，即有選擇性地進(jìn)行漏電保護(hù)，不會(huì)像檢漏繼電器那樣，一旦電網(wǎng)某處發(fā)生漏電就引起整個(gè)電網(wǎng)總停電、采區(qū)全停產(chǎn)。但也有缺點(diǎn)或局限性，它對(duì)三相同時(shí)漏電是無(wú)法檢測(cè)與保護(hù)的，不能對(duì)三相對(duì)稱性漏電故障進(jìn)行保護(hù)。零序功率方向式選擇性漏電保護(hù)的缺點(diǎn)是原理性和先天性的，選擇性漏電保護(hù)設(shè)備本身無(wú)法克服。
and completes the predetermined operation through comparison or interruption. The special input points for each high-speed counter are shown in the table below:
3. Status byte of high speed counter
The system provides a status byte for each high-speed counter in the special register area SMB. In order to monitor the working status of the high-speed counter, the system executes the interrupt event referenced by the high-speed counter. Its format is as follows:
The status bit of the status byte is valid only when the interrupt program of the high-speed counter is executed.
4. Working mode of high speed counterThe high-speed counter has 12 different working modes (0 ` ~ 11), which are divided into 4 categories. Each high-speed counter has a variety of working modes. The working mode can be selected by programming and using the definition high-speed counter instruction HDEF.
(1) Working mode of each high countera. High speed counter hc0 is a general increase / decrease counter with 8 modes. Different working modes can be selected through programming. The working modes of hc0 are as follows:
b. There are 12 modes of high-speed counter HC1, as shown in the table below:
c. High speed counter HC2 has 12 modes, as shown in the table below:
d. High speed counter HC3 has one mode, as shown in the table below:
