Understanding what it is that it serves compensatorIt is fundamental to any engineer or electrician engaged in the maintenance of high-voltage circuit breakers. This node is a complex mechanical device that plays a critical role in the stability of the entire switching system. Without its correct operation, it is impossible to guarantee reliable disconnection of short-circuit currents or normal loads.
The design is based on the need to compensate for changes in ambient temperatures. The physical properties of materials such as oil and metal are known to change when heated or cooled. It is for the purpose of leveling these processes and is intended LCDThis prevents false positives or, conversely, sticking of contacts.
In this article, we will discuss in detail the principle of operation of this element, its device and typical malfunctions. You will learn how temperature fluctuations affect the hydraulic drive and why ignoring the maintenance of the compensator can lead to an emergency situation at the substation.
Main purpose and working principle
The main function for which it serves compensatorIt is the stabilization of the pressure of the working fluid inside the tank of the switch. When the temperature changes, the volume of oil in the system changes: when heated, it expands, and when cooled, it shrinks. If there were no compensating mechanism, these volumetric changes would lead to either depressurization of the tank or the formation of a vacuum.
The principle of operation of the device is based on the mobility of the piston or bellows, which separates the air and oil cavities. When the oil expands, the piston shifts, displacing the excess into a special container or compressing the gas cushion. This process is smooth and does not affect the readiness of the switch to switch.
However, it is worth remembering that the mechanism responds not only to temperature, but also to the level of oil. AKM System This allows the operator to visually or instrumentally monitor the insulation environment. This makes the device an important element of monitoring the technical condition of high-voltage equipment.
- 🔧 It stabilizes internal pressure during thermal expansion of oil.
- 🔧 Prevents the ingress of moisture and oxygen into the oil tank.
- 🔧 Provides the ability to add oil without stopping the switch.
- 🔧 It serves as an indicator of the level of working fluid in the system.
⚠️ Attention: Snagging of the piston of the compensator in the lower position can lead to the squeeze of oil through the seals during sharp heating, which creates a risk of fire.
Design features of the mechanism
Constructively AKM compensator is a cylindrical body, inside which a moving element moves. Depending on the switch model (e.g., VMI-133 or VS-10), the design may have its own characteristics, but the general principle remains unchanged. The tightness is provided by special sealing rings that require periodic replacement.
The top of the device usually communicates with the atmosphere through a filter-dryer, which prevents condensation from forming inside the system. The lower part is rigidly connected to the oil tank of the switch. This separation allows you to isolate the working environment from external contaminants, keeping the dielectric properties of the oil at a high level.
An important element is the level indicator, which is often integrated directly into the housing of the compensator. It allows you to quickly assess how much oil It's normal. The absence of a visible level in the viewing window may indicate both a leak and a malfunction of the pointer itself.
The effect of temperature on the operation of the switch
Temperature is crucial for longevity oil-switch. In summer, on hot days, oil can be heated not only by air temperature, but also by the passing current of the load. At this moment AKM compensator takes on the main load for the expansion of the volume of liquid.
In winter, the situation changes to the opposite. With severe frosts, the oil thickens and decreases in volume. If the compensator does not perform its function, a vacuum may occur in the system, which will lead to the sucking of moist air through the looseness. The moisture in the oil drastically reduces its penetrating stress.
Temperature changes in the off-season are especially critical. A sharp cooling after warm weather creates a dynamic load on the moving parts of the mechanism. Hydraulic system It must be able to respond to these changes to maintain the pressure.
- ❄️ At -40°C, the volume of oil is significantly reduced, requiring a piston power reserve.
- ☀️ At +40°C, the compensator may overflow in the absence of free volume.
- 🌡️ Cyclic changes cause wear of the sealing cuffs.
Effects of air humidity
If the dehumidifier filter at the top of the compensator is clogged or lost, moist air enters the interior. During night cooling, moisture condenses on the walls and drains into the oil, reducing its insulating properties by 30-40%.
Typical malfunctions and their diagnosis
During operation compensator It is subject to a number of characteristic malfunctions. The most common problem is the loss of seal seal seal seals. The oil begins to seep out, leaving characteristic flows on the body of the switch. This not only creates a fire hazard situation, but also reduces the level of insulation.
Another common problem is jamming the movable piston. This can occur due to contamination of the oil by wear or oxidation products. As a result, the compensator ceases to perform its function, and when the temperature changes, the pressure in the tank goes beyond the permissible limits.
Diagnosis of the state of the device is carried out visually and instrumentally. The operator must pay attention to the level of oil in the index and the presence of external leaks. It is also recommended to periodically check the mobility of the mechanism during preventive work.
| Malfunction | Sign. | Consequence | Elimination method |
|---|---|---|---|
| Wearing the cuff | Oil leaks on the shell | Lower oil levels, risk of breakdown | Replacement of seals |
| Piston jamming | Immobility of level indicator | Depressurization or deformation of the tank | Machine audit, cleaning. |
| Filter contamination | Increased humidity inside | Moisturizing the oil, reducing strength | Replacement of silica gel/filter |
| Mechanical damage | Cracks in the hull, skewed | Total loss of functionality | Replacement of the entire node |
⚠️ Attention: Detecting traces of oil on the ground under the switch requires immediate equipment removal for repair, as the level of insulation can be critically low.
Service and audit arrangements
Regular maintenance AKM compensator is included in the list of mandatory works during the overhaul of the switch. Before starting work, you must make sure there is no voltage on the equipment and ground the current parts. Only then can you start dismantling or revision of the nodes.
The maintenance process includes draining the oil from the compensator, disassembling the body, cleaning the parts from the sludge and replacing the seals. Particular attention should be paid to the condition of the inner surface of the cylinder - it should not be bullying or corrosion.
After assembly and installation of the unit in place, vacuuming and filling with fresh transformer oil is performed. It is important to remove all air traffic jams to ensure that the compensation mechanism works properly.
☑️ Checklist of compensator audit
When assembling the compensator, lubricate the rubber seals with a thin layer of the same transformer oil that will be poured into the switch. This will prevent cuffs from twisting during installation.
Relationship with other switch nodes
We can't look at it. compensator in isolation from the rest of the circuit breaker. It is directly connected to the oil tank, the arc-extinguishing chamber and the drive mechanism. Violation of the compensator inevitably affects the speed of opening contacts and the ability to extinguish the arc.
For example, if due to a malfunction of the compensator, the oil level falls below the permissible level, the combustion products of the arc will not have time to cool. This will lead to a sharp increase in pressure inside the tank and a possible explosion. Therefore compensation It is a key element of security.
It is also worth noting the connection with level indicators and alarms. In modern monitoring systems, level sensors are often installed in the zone of the compensator, transmitting data on the state of the oil to the control room in real time.
- 🔗 It affects the pressure in the tank when the arc burns.
- 🔗 It's connected to the ventilation and filtration system.
- 🔗 Determines the correctness of the readings of levelers.
A proper AKM compensator is a guarantee that the switch will withstand heat loads in any season of the year without breaking the tightness.
How often should I check the oil level in the compensator?
Visual inspection of the oil level is recommended monthly, as well as after each switch switch short circuit currents. A complete revision with the replacement of oil and seals is carried out according to the schedule of the RPR (usually every 6-12 years, depending on the type of switch).
Can I add oil to the compensator under tension?
Adding oil to a running switch (under voltage) is strictly prohibited by safety rules, unless it is provided for by a special design with an insulated funnel and special protection measures. Usually the work is carried out on disconnected and grounded equipment.
What to do if the compensator piston is jammed?
The switch must be removed for repair. Attempts to develop a jammed piston without disassembly can lead to damage to the body. It is required to drain the oil, dismantle the compensator, clean the parts of oxides and replace the deformed elements.
What type of oil is used in the ACM compensator?
As a rule, the same transformer oil is used as in the switch tank (for example, TKP, GC, VG). It is important that the oil is dry and has no mechanical impurities, as they can damage the piston seals.