JFY-2 type negative sequence voltage relayDetailed product description：

Purpose:

JFY-2 negative sequence voltage relay is used as a discrimination element for two-phase short circuit faults in systems or equipment. Combined with low-voltage relays to form composite voltage components, used as blocking elements for current relays.
The setting of JFY-2 negative sequence voltage relay is carried out using the dial switch on the panel, which is intuitive and convenient.

Working Principle:
The block diagram is shown in Figure 1. The voltage measurement circuit consists of a voltage converter, a phase shifter, and an adder. UCK2 is delayed by 120 ° by a phase shifter and added to UCK1 to form the negative sequence voltage filter output UCK5.
UCK5=UCK1+UCK2 ∠ -120 °.
Make the transformation ratio KYH1 of voltage converter YH1 the same as the transformation ratio KYH2 of YH2.
When KYH1=KYH2=KYH, UAC=UBC=U1, UCK1 = UCK2 = U1/KYH。
Select the appropriate parameters so that UCK5=0V when inputting three-phase positive sequence voltage, as shown in Figure 2 (a)
Therefore, when inputting three-phase negative sequence voltage, UCK5 = 3U1/KYH， Refer to Figure 2 (b).
The output UCK5 of the negative sequence voltage filter is compared with the threshold voltage UCK7 obtained by setting, rectifying, filtering, and level detection. During normal operation and symmetrical three-phase short circuit, UCK5=0V， The filtered output UCK6 is also 0V. The level detection output is a positive signal, and the relay does not operate. When a two-phase short circuit occurs and the negative sequence voltage value reaches UCK6>UCK7, the level detection outputs a negative signal and the relay operates.



Main technical parameters:
5.1 AC rated voltage: 110V, 50Hz.
5.2 DC rated voltage: 110V, 220V.
5.3 Power consumption: AC voltage circuit. Power consumption per phase under rated voltage ≤ 1VA; DC voltage circuit, ≤ 3W under rated voltage 110V; ≤ 4W under rated voltage 220V.
5.4 Negative sequence voltage setting range: 2-21.8V, with a step difference of 0.2V.
5.5 Scale error: not exceeding ± 5%.
The discrete value of various two-phase short-circuit action voltages is ≤ 5%.
5.7 Return coefficient: ≥ 0.9.
5.8 Action time: ≤ 25ms tested at twice the action voltage.
5.9 Allowable ambient temperature: -10 ℃ to+50 ℃.
5.10 Contact breaking capacity
a) DC circuit: Under the conditions of current not exceeding 2A and voltage not exceeding 250V, the external output contact can disconnect a DC inductive load of 30W with a time constant of 5ms ± 0.75ms.
b) AC circuit: Under the conditions of current not exceeding 1A and voltage not exceeding 250V, the external output contact can disconnect the load of the circuit with a power factor coso of 0.4 ± 0.1 at 250VA.
5.11 Dielectric Strength
The conductive circuits of the relay should be able to withstand an AC test voltage of 2kV (effective value) and 50Hz between the exposed non charged metal parts and the casing, as well as between the input circuit contacts, for a duration of 1 minute without insulation breakdown or flashover.
5.12 Working conditions
a) The usage location does not allow explosive media, and the surrounding media should not contain corrosive metals, gases that damage insulation, or conductive media. It is not allowed to be filled with water vapor or have serious mold presence;
b) Strong vibrations and impacts are not allowed in the usage location;
c) The usage location should have facilities to defend against rain, snow, wind, and sand;
d) The usage location does not allow an external magnetic induction intensity exceeding 1.5mT.
5.13 Electrical anti-interference relays shall comply with GB7261 and GB6261 "Electrical anti-interference tests for static relays and protective devices".

Rear wiring diagram of JFY-2 negative sequence voltage relay:



Relay external dimensions and opening dimensions:
Refer to Figures 2 and 6 in the protruding modular insertion structure.

Ordering instructions:
7.1 Product model, name, structural form, etc.
7.2 Order Quantity.
7.3 Relay matching: such as base, socket, etc. (must be ordered separately).

JFY-2 type negative sequence voltage relay（No image available）