Abstract: the necessity of applying residual current, the main functions, working principle, classification situation of ASJ residual current relay are introduced, and the principles and precautions in selecting residual current protection circuit breaker are indicated. This is a brief introduction about the addition of our company application of ASJ residual current relay in a generator set project in Maldives.

 

關鍵詞：ASJ剩余電流繼電器；發電機組；應用。

Keywords: ASJ residual current relay; generator set; application.

 

1.項目概述 Project overview

本項目位于馬爾代夫，安裝剩余電流繼電器是為了檢測剩余電流，將剩余電流值與基準值相比較，當剩余電流值超過基準值時，發出一個機械開閉信號（使機械開關電器脫扣或聲光報警裝置發出報警）。剩余電流繼電器通常與低壓斷路器或低壓接觸器等組成組合式剩余電流保護裝置，主要適用于交流50Hz，額定電壓400V及以下的TT和TN系統配電線路，用來對電氣線路進行接地故障保護，防止接地故障電流引起的設備損壞和電氣火災事故，也可用來對人身觸電危險提供間接接觸保護，因而低壓供配電系統中廣泛應用。

This project is located in Maldives. The purpose of the residual current relay installed is to detect the residual current and compare the residual current value with the base value. When the residual current value exceeds the base value, it will send out a mechanical on-off signal (to make the mechanical switch tripped or the acousto-optic alarm device send out an alarm).Residual current relay usually with low voltage circuit breaker or low voltage contactor, etc combined residual current protection device, mainly applied to ac 50 hz, rated voltage 400 v and below the TT and TN system distribution circuit, used to ground fault protection electric circuit, prevent equipment damage caused by ground fault current and electrical fire accident, also can be used to provide indirect contact to person get an electric shock risk protection, and therefore is widely used in low voltage power supply and distribution system.

 

 

2.剩余電流繼電器主要用途 Main uses of residual current relay

2.1 間接接觸電擊保護 Protection of Indirect Contact Electric Shock 

間接接觸電擊保護的措施是自動切斷電源。GB 13955“對間接接觸電擊事故的防護"規定：“間接接觸電擊事故防護的主要措施是采用自動切斷電源的保護方式，以防止由于電氣設備絕緣損壞發生損壞事故。當電路發生絕緣損壞造成接地故障。其故障電流值小于過電流保護裝置的動作電流值時，應安裝剩余電流保護裝置。"研究表明，人體接觸電壓的安全值為 50 V。為保證人身安全，電氣裝置的任何部分發生絕緣故障時，一旦接觸電壓超過 50 V 時，需要在規定的時間內自動切斷故障部分電源。過電流保護裝置受電氣線路和設備及自身動作值限制，不能自動切斷電源。剩余電流保護裝置不受負荷電流影響，可與過電流保護裝置配合使用，作間接接觸電擊保護 。

The measure of indirect contact electric shock protection is to automatically cut off the power supply. GB 13955" the protection of indirect contact electric shock accident "stipulates :" the main measure of indirect contact electric shock accident protection is to adopt the protection mode of automatically cutting off the power supply to prevent the damage accident caused by the insulation damage of electrical equipment. When the circuit insulation damage caused by grounding fault. When the fault current value is less than the operating current value of the over-current protection device, the residual current protection device shall be installed ." According to the research, the safe value of contact voltage is 50V. For personal safety, when insulation failure occurs in any part of the electrical device, once the contact voltage exceeds 50V, it is necessary to automatically cut off the fault part of the power supply within the specified time. The over-current protection device is limited by the electrical circuit and equipment and its own action value, and can not automatically cut off the power supply. The residual current protection device is not affected by the load current and can be used in conjunction with the over-current protection device for indirect contact electric shock protection.

 

2.2 接地故障保護 Ground fault protection

接地是帶電導體和大地、接地的金屬外殼或與地有聯系的構件之間的接觸，其故障可能導致人身電擊傷亡和設備損壞，嚴重時可能引發電氣火災。接地故障保護過去通常采用過電流保護裝置進行保護，當接地故障電流大于過電流保護裝置定值時，由過電流保護裝置切斷故障電路。

TT系統中額定電流較大、配電線路較長的線路，TN系統中帶電導線落地接地故障、不安全的金屬性接地故障、電弧性接地故障時，都有可能出現接地故障電流小于過電流保護動作整定電流，過電流保護裝置不動作的情況。剩余電流保護裝置，或帶接地故障保護的斷路器，能可靠地進行接地故障保護。

Grounding is the contact between a live conductor and the earth, a grounded metal shell or a component connected to the ground. Its failure may lead to personal electric shock casualties and equipment damage, and may cause electrical fire in serious cases. Ground fault protection used to be protected by over-current protection device. When the grounding fault current is greater than the fixed value of the over-current protection device, the fault circuit is cut off by the over-current protection device. 

In TT system, the line with larger rated current and longer distribution line, grounding fault of live conductor, unsafe metallic grounding fault and arc grounding fault in TN system may occur that the grounding fault current is less than the setting current of over-current protection action, and the over-current protection device does not act. Residual current protection device, or circuit breaker with ground fault protection, can reliably carry out ground fault protection.

 

2.3 電氣火災保護 Electrical fire protection

電氣火災通常由電氣短路引起，電氣短路包括金屬性短路和電弧性短路。前者是帶電導體間（如相與相之間、相與 N 線之間）短路，多以高溫熔焊金屬為通路，故障電流以千安計，高溫易使絕緣氧化而自燃，火災危險雖大，但可用帶短路保護的斷路器和熔斷器保護，由斷路器瞬時動作切斷電源，避免火災。后者是帶電導體對地短路，多以電弧為通路，故障電流雖小，但一方面電弧長時間延續，局部溫度高，很容易點燃周邊可燃物質，引發火災；另一方面，又不足以使一般斷路器動作跳閘切斷電源。所以電弧性短路引起火災危險遠大于金屬性短路。帶剩余電流動作保護功能的斷路器可在過電流保護裝置不動作的情況下切斷保障電路，防止電弧性短路引發的電氣火災。

Electrical fire is usually caused by electrical short circuit, which includes metal short circuit and arc short circuit. The former is a short circuit between live conductors (such as between phases, between phases and N lines). The fault current is calculated in kilo ampere. High temperature is easy to cause insulation oxidation and spontaneous combustion. 

Although the fire hazard is great, it can be protected by circuit breakers and fuses with short circuit protection, and the power supply is cut off by instantaneous action of circuit breaker to avoid fire. The latter is a live conductor short circuit to the ground, mostly arc as the path, although the fault current is small, but on the one hand, the arc lasts for a long time, the local temperature is high, it is easy to ignite the surrounding combustible material and cause fire. Therefore, the fire hazard caused by arc short circuit is much greater than that of metal short circuit. The circuit breaker with residual current action protection function can cut off the support circuit without the operation of the over-current protection device to prevent the electrical fire caused by the arc short circuit.

 

3.ASJ系列剩余電流繼電器 ASJ Series of Residual Current Relay

3.1 型號和功能  Model & Function

3.2 技術參數 Technical Parameters