Let's take a look one by one:

(1), the forced current method of cathodic protection, the advantages are 1, the output current is continuously adjustable 2, the protection range is large 3, not limited by the environmental resistivity 4, the larger the project is more economic 5, the protection device life is long. Disadvantages are: 1, high resistivity environment is not suitable for use; 2, the protection current is almost unadjustable; 3, the quality of the cover layer must be good; 4, the commissioning work is complex; 5, the consumption of non-ferrous metals

(3) The advantages of cathodic protection with polar discharge are: 1. Pipeline 2, economical and practical 3, simple method, only simple management 4, when there is stray current, can automatically prevent the erosion of stray current shortcomings are 1, interference on other structures 2, interference shutdown, the protection body can not be protected 3, easy to cause too negative potential.

There are three ways of cathodic protection, which are forced current method, sacrificial anode method and discharge protection law, among which the discharge protection law is divided into polar discharge and mandatory discharge.

(2) the advantages of the sacrifical anode method of cathodic protection are: 1, no external power supply is needed; 2, no interference or small to adjacent structures; 3, no need for treatment after commissioning; 4, the project is smaller and more economical; 5, the protection current distribution is average and the utilization rate is high. The disadvantages are 1, the need for external power supply 2, interference to adjacent metal structures 3, maintenance and management workload.

The advantages of the forced discharge of cathodic protection are: 1. Wide protection range; 2. Continuous adjustable voltage and current; 3. The disadvantages are 1, have an impact on other structures 2, need external power supply 3, the discharge point is easy to protect.