EPRO PR9268/307-100前置傳感器基于智能保護器RPC2701的礦用隔爆型真空饋電開(kāi)關(guān)在煤礦井下三相中性點(diǎn)不接地的供電系統中，礦用隔爆型真空饋電開(kāi)關(guān)可以作為井下配電系統的總開(kāi)關(guān)或分支開(kāi)關(guān)來(lái)使用，也可以作為大容量電動(dòng)機在不頻繁起動(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(kāi)關(guān)專(zhuān)用智能保護器RPC2701作為礦用隔爆型真空饋電開(kāi)關(guān)的保護器，滿(mǎn)足漏電保護裝置對快速性和穩定性的要求，可以完成礦井低壓電網(wǎng)的二級選擇性漏電保護、對稱(chēng)短路保護、不對稱(chēng)短路保護、斷相保護、過(guò)載保護和過(guò)電壓保護等功能。
EPRO PR9268/307-100前置傳感器3.1 礦用隔爆型真空饋電開(kāi)關(guān)的操作界面專(zhuān)用智能保護器RPC2701通過(guò)RS-232串行通訊口與觸摸屏HMI進(jìn)行通訊，并預留RS-485串行通訊口與上一級通訊分站進(jìn)行通訊。礦用隔爆型真空饋電開(kāi)關(guān)的漏電保護系統由兩部分組成，其中一部分是基于附加直流檢測的總漏電保護系統，另外一部分是基于零序電流方向判斷的分支漏電保護系統。該漏電保護系統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)對稱(chēng)漏電時(shí)保護動(dòng)作的穩定性，使饋電開(kāi)關(guān)既可靠又安全。礦用隔爆型真空饋電開(kāi)關(guān)的電氣原理圖如圖3所示。 3.2.1 基于附加直流檢測的總漏電保護系統附加直流電源檢測式漏電保護原理示意圖如圖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電網(wǎng)對地絕緣電阻的變化。當直流電壓一定時(shí)，檢測的電阻值變化。當絕緣電阻下降到表1規定的動(dòng)作值時(shí)，PLC程序調用中斷進(jìn)行立即輸出，使繼電器動(dòng)作，其常開(kāi)觸點(diǎn)接通饋電開(kāi)關(guān)的分勵脫扣線(xiàn)圈，使開(kāi)關(guān)跳閘，實(shí)現漏電保護，并通過(guò)液晶顯示屏將對地電阻值直觀(guān)地顯示出來(lái)。附加直流電源檢測式漏電保護系統具有保護全面和動(dòng)作無(wú)死區等優(yōu)點(diǎn)，但也具有動(dòng)作無(wú)選擇性和動(dòng)作時(shí)間長(cháng)等缺點(diǎn)。對于1140V等級，1K的漏電動(dòng)作時(shí)間不大于30ms。礦用低壓防爆饋電開(kāi)關(guān)的選擇性漏電保護是指當礦井低壓電網(wǎng)某條支路的某一相發(fā)生人身觸電、或單相對地放電、或單相對地泄漏電流時(shí)，能及時(shí)檢測出漏電故障并作用于跳閘，有選擇性地只切斷故障線(xiàn)路，保證非故障線(xiàn)路安全運行的保護設施。當電網(wǎng)非對稱(chēng)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，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，再判斷是否達到門(mén)檻值，最后啟動(dòng)執行電路，切斷故障支路的電源，實(shí)現有選擇性的漏電保護。零序功率方向式選擇性漏電保護具有很強的橫向選擇性，即有選擇性地進(jìn)行漏電保護，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、采區全停產(chǎn)。但也有缺點(diǎn)或局限性，它對三相同時(shí)漏電是無(wú)法檢測與保護的，不能對三相對稱(chēng)性漏電故障進(jìn)行保護。零序功率方向式選擇性漏電保護的缺點(diǎn)是原理性和先天性的，選擇性漏電保護設備本身無(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:
