Connection mode of electric power network and its calculation

The power network can be divided into series, parallel and hybrid according to the detonator connection.

First, the series. It is a method of connecting electric detonators one by one in series and then connecting with a power source. The advantage of this method is that the connection is simple, the operation is easy, the total current required is small, and the wire consumption is small. The disadvantage is that if there is a detonator open circuit in the network, the entire network will be disconnected and the explosion will be refused.

(1) Total resistance R: R = R _x + nr, Ω

In the formula:

R _x - wire resistance, Ω;

Number of n-series electric detonators;

R-single electric detonator resistance, Ω.

(2) Total network current I:

In the formula:

U- supply voltage, V.

Second, parallel. Parallel connection is a method in which two foot wires of all electric detonators are respectively connected to two wires, and then the two wires are connected to a power source. The advantage of the parallel network is that it does not cause the detonation of other detonators due to one of the detonators being disconnected. The total resistance of the network is small. The disadvantage is that the total current of the network is large, and the wires of the connecting lines are consumed. If a small number of detonators are missed, the inspection is not easy to find.

(1) Total network resistance R:

R=R _x +r/m, Ω

In the formula:

The number of m-parallel electric detonators.

(2) Total network current I:

(3) Current obtained by each electric detonator i:

In the formula:

i _x - the quasi-explosive power of the current detonator.

Third, mixed. Hybrid is a hybrid coupling method that combines in series and parallel in a power network. Can be divided into two series of series and parallel and parallel.

In series and parallel, several electric detonators are connected in series, then several series groups are connected in parallel on two wires, and then connected to the power supply. In series, two detonators are connected in parallel in each blasthole, and all parallel groups are connected in series.

(1) Total network resistance R:

(2) Total network current I;

(3) Current obtained by each detonator i:

In the formula:

When n-series is connected in parallel, the number of series in series; and in series is the number of series groups;

When m- is connected in series, the number of parallel detonators in a group is the number of parallel groups in series and parallel.

The advantage of a hybrid network is that it has the advantages of series and parallel, and at the same time it can detonate a large number of electric detonators.