In harsh environments characterized by high temperature, high humidity, or strong electromagnetic interference, the performance of DP current transformers can be affected in various ways. Targeted protective measures are essential to ensure their stable operation, as detailed below:
I. Impact and Protection in High - Temperature Environments
(I) Performance Impact
High temperatures accelerate the aging of the insulation materials in DP current transformers, reducing their insulation properties and increasing the risk of electrical leakage. Additionally, the resistance of the windings increases with temperature rise, leading to larger measurement errors and affecting metering accuracy. Excessively high temperatures can also alter the magnetic properties of the core, causing magnetic saturation, which further diminishes the transformer's transformation accuracy. In severe cases, this may trigger malfunctions in the relay protection devices.
(II) Protective Measures
Employ high - temperature - resistant insulation materials, such as polyimide film and silicone rubber, to enhance the heat resistance rating of the insulation system. In the structural design of the transformers, incorporate heat sinks or optimize the heat dissipation channels to enhance natural convection heat dissipation. For applications with stringent requirements, equip the transformers with forced air - cooling or liquid - cooling devices to lower the operating temperature. Install temperature monitoring devices to continuously monitor the transformer's temperature. When the temperature exceeds the preset threshold, issue timely warnings and implement cooling measures.
II. Impact and Protection in High - Humidity Environments
(I) Performance Impact
In high - humidity conditions, moisture can easily penetrate the interior of DP current transformers, causing the insulation materials to become damp. This leads to a decrease in insulation resistance and increases the likelihood of insulation breakdown. Moisture may also condense into water droplets inside the transformers, corroding metal components like windings and cores, which in turn affects the mechanical strength and electrical performance of the transformers. Prolonged exposure to such environments significantly shortens the equipment's service life.
(II) Protective Measures
Seal the transformers thoroughly and use casings and joints with excellent sealing performance to prevent moisture ingress. Place desiccants, such as silica gel, inside the transformers to absorb residual moisture. Opt for insulation materials and surface coatings with moisture - resistant properties to improve the overall moisture resistance. Conduct regular insulation inspections on the transformers to promptly detect and address any moisture - related issues.
III. Impact and Protection in Strong Electromagnetic Interference Environments
(I) Performance Impact
Strong electromagnetic interference can induce interference signals on the secondary side of DP current transformers, resulting in measurement result deviations. In severe cases, it may cause secondary equipment to misinterpret the signals, disrupting the normal operation of relay protection and automation systems. Moreover, the interference can trigger malfunctions in the internal electronic components of the transformers and damage sensitive circuits.
(II) Protective Measures
Implement effective shielding designs for the transformers, utilizing metal shielding covers or shielded cables to isolate them from the strong external electromagnetic environment. Install filtering devices, such as electromagnetic interference filters, in the secondary circuits to suppress high - frequency interference signals. Optimize the grounding methods of the secondary circuits, adopting single - point grounding or multi - point grounding to ensure reliable grounding and minimize the impact of electromagnetic interference.